skint/src/n.sf

;  LibN: Large RNRS compatibility library for #F, fixnum/flonum arithmetics 

;  #F's predefined forms: 
;
;  begin define define-syntax if lambda quote
;  set! syntax-lambda syntax-rules


;------------------------------------------------------------------------------

; basic syntax constructs, extended lambda

(define-syntax syntax-rule
  (syntax-rules ()
    [(_ pat tmpl) (syntax-rules () [(__ . pat) tmpl])]))

(define-syntax let-syntax
  (syntax-rules ()
    [(_ ([kw init] ...))
     (begin)]
    [(_ ([kw init] ...) . body)
     ((syntax-lambda (kw ...) . body)
      init ...)]))

(define-syntax letrec-syntax
  (let-syntax ([let-syntax let-syntax] [define-syntax define-syntax])
    (syntax-rules ()
      [(_ ([kw init] ...) . body)
       (let-syntax ()
         (define-syntax kw init) ... (let-syntax () . body))])))

(define-syntax lambda
  (let-syntax ([old-lambda lambda])
    (letrec-syntax
      ([loop
        (syntax-rules ()
          [(_ (narg . more) (arg ...) . body) 
           (loop more (arg ... narg) . body)]
          [(_ rarg (arg ...) . body)
           (make-improper-lambda ; see definition below
             #&(length (arg ...)) 
             (old-lambda (arg ... rarg) (let-syntax () . body)))])])
      (syntax-rules ()
        [(_ (arg ...) . body)
         (old-lambda (arg ...) (let-syntax () . body))]
        [(_ args . body)
         (loop args () . body)]))))


; definition forms

(define-syntax define
  (let-syntax ([old-define define])
    (letrec-syntax
      ([new-define
        (syntax-rules ()
          [(_ exp) (old-define exp)]
          [(_ (var-or-prototype . args) . body)
           (new-define var-or-prototype (lambda args . body))]
          [(_ . other) (old-define . other)])])
     new-define)))

(define-syntax define-inline
  (letrec-syntax 
    ([loop
      (syntax-rules ()
        [(_ id ([v e] ...) () . body) 
         (begin
           (define-syntax id
             (syntax-rules ()
               [(_ e ...)
                ((lambda (v ...) . body) e ...)]
               [_ #&(string->id #&(string-append "%residual-" #&(id->string id)))]))
           (define #&(string->id #&(string-append "%residual-" #&(id->string id)))
             (lambda (v ...) . body)))]
        [(_ id (b ...) (v . vs) . body)
         (loop id (b ... [v e]) vs . body)])])
    (syntax-rules ()
      [(_ (id v ...) . body)
       (loop id () (v ...) . body)]
      [(_ #&(id? id) val)
       (define-syntax id val)])))
     
(define-syntax define-integrable
  (syntax-rules ()
    [(_ (op . ll) . body)
     (define-syntax op 
       (%quote (letrec ([op (lambda ll . body)]) op)))]))


; primitive definition helpers

(define-syntax %prim*/rev
  (letrec-syntax
    ([loop
      (syntax-rules ()
        [(_ prim () args)
         (%prim* prim . args)]
        [(_ prim (arg . more) args) 
         (loop prim more (arg . args))])])
    (syntax-rules ()
      [(_ prim arg ...) 
       (loop prim (arg ...) ())])))


; binding forms

(define-syntax let
  (syntax-rules ()
    [(_ ([var init] ...) . body)
     ((lambda (var ...) . body) init ...)]
    [(_ name ([var init] ...) . body)
     ((letrec ([name (lambda (var ...) . body)])
        name)
      init ...)]))

(define-syntax let*
  (syntax-rules ()
    [(_ () . body) (let () . body)]
    [(_ ([var init] . bindings) . body)
     (let ([var init]) (let* bindings . body))]))

(define-syntax letrec
  (syntax-rules ()
    [(_ ([var init] ...) . body)
     (let () (define var init) ... (let () . body))]))
     
(define-syntax letrec*
  (syntax-rules ()
    [(_ ([var expr] ...) . body)
     (let ([var #f] ...)
       (set! var expr)
       ...
       (let () . body))]))

(define-syntax rec
  (syntax-rules ()
    [(_ (name . args) . body)
     (letrec ([name (lambda args . body)]) name)]
    [(_ name expr)
     (letrec ([name expr]) name)]))

(define-syntax letcc
  (let-syntax ([old-letcc letcc])
    (syntax-rules ()
      [(_ var . body)
       (old-letcc var (let-syntax () . body))])))
       
(define-syntax receive
  (syntax-rules ()
    [(_ formals expr . body)
     (call-with-values 
       (lambda () expr)
       (lambda formals . body))]))

(define-syntax let*-values
  (syntax-rules ()
    [(_ () . body) (let () . body)]
    [(_ ([(a) x] . b*) . body) (let ([a x]) (let*-values b* . body))]
    [(_ ([aa x] . b*) . body) (call-with-values (lambda () x) (lambda aa (let*-values b* . body)))]))

(define-syntax let-values
  (letrec-syntax
    ([loop 
      (syntax-rules ()
        [(_ (new-b ...) new-aa x map-b* () () . body)
         (let*-values (new-b ... [new-aa x]) (let map-b* . body))]
        [(_ (new-b ...) new-aa old-x map-b* () ([aa x] . b*) . body)
         (loop (new-b ... [new-aa old-x]) () x map-b* aa b* . body)]
        [(_ new-b* (new-a ...) x (map-b ...) (a . aa) b* . body)
         (loop new-b* (new-a ... tmp-a) x (map-b ... [a tmp-a]) aa b* . body)]
        [(_ new-b* (new-a ...) x (map-b ...) a b* . body) 
         (loop new-b* (new-a ... . tmp-a) x (map-b ... [a tmp-a]) () b* . body)])])
    (syntax-rules ()
      [(_ () . body) (let () . body)]
      [(_ ([aa x] . b*) . body)
       (loop () () x () aa b* . body)])))

#;(define-syntax set!-values
  (letrec-syntax
    ([loop 
      (syntax-rules ()
        [(_ new-aa ([a tmp-a] ...) () x)
         (call-with-values (lambda () x) (lambda new-aa (set! a tmp-a) ...))]
        [(_ (new-a ...) (map-a ...) (a . aa) x) 
         (loop (new-a ... tmp-a) (map-a ... [a tmp-a]) aa x)]
        [(_ (new-a ...) (map-a ...) a x) 
         (loop (new-a ... . tmp-a) (map-a ... [a tmp-a]) () x)])])
    (syntax-rules ()
      [(_ () x) (define x)]
      [(_ aa x) (loop () () aa x)])))

(define-syntax define-values
  (letrec-syntax
    ([loop 
      (syntax-rules ()
        [(_ new-aa ([a tmp-a] ...) () x)
         (begin
           (define a (void)) ...
           (define (call-with-values (lambda () x) (lambda new-aa (set! a tmp-a) ...))))]
        [(_ (new-a ...) (map-a ...) (a . aa) x) 
         (loop (new-a ... tmp-a) (map-a ... [a tmp-a]) aa x)]
        [(_ (new-a ...) (map-a ...) a x) 
         (loop (new-a ... . tmp-a) (map-a ... [a tmp-a]) () x)])])
    (syntax-rules ()
      [(_ () x) (define x)]
      [(_ aa x) (loop () () aa x)])))


; control
               
(define-syntax when
  (syntax-rules ()
    [(_ test . body) (if test (let-syntax () . body))]))

(define-syntax unless
  (syntax-rules ()
    [(_ test . body) (if test (if #f #f) (let-syntax () . body))]))

(define-syntax cond
  (syntax-rules (else =>)
    [(_) (if #f #f)] ; undefined
    [(_ [else . exps]) (let () . exps)]
    [(_ [x] . rest) (or x (cond . rest))]
    [(_ [x => proc] . rest)
     (let ([tmp x]) (cond [tmp (proc tmp)] . rest))]
    [(_ [x . exps] . rest)
     (if x (let () . exps) (cond . rest))]))

(define-syntax and
  (syntax-rules ()
    [(_) #t]
    [(_ test) (let () test)]
    [(_ test . tests) (if test (and . tests) #f)]))

(define-syntax or
  (syntax-rules ()
    [(_) #f]
    [(_ test) (let () test)]
    [(_ test . tests) (let ([x test]) (if x x (or . tests)))]))

(define-syntax do
  (let-syntax ([do-step (syntax-rules () [(_ x) x] [(_ x y) y])])
    (syntax-rules ()
      [(_ ([var init step ...] ...)
         [test expr ...]
          command ...)
       (let loop ([var init] ...)
         (if test
             (begin (if #f #f) expr ...)
             (let () 
               command ...
               (loop (do-step var step ...) ...))))])))


;------------------------------------------------------------------------------

; scheme data types 


(%definition "/* basic object representation */")

; there are two types of immediate objects: those with 30 bits of payload data
; and no secondary tag (lower two bits are 11), and those with 3-bit tag and 24 
; bits of payload data (lower two bits are 01); in both cases lsb is 1

(%definition "#define isim0(o)    (((o) & 3) == 3)")
(%definition "#define isimm(o, t) (((o) & 0xff) == (((t) << 2) | 1))")

(%definition "#ifdef NDEBUG
  #define getim0s(o) (long)((((o >> 2) & 0x3fffffff) ^ 0x20000000) - 0x20000000)
  #define getimmu(o, t) (long)(((o) >> 8) & 0xffffff)
#else
  extern long getim0s(obj o);
  extern long getimmu(obj o, int t);
#endif")

(%localdef "#ifndef NDEBUG
long getim0s(obj o) {
  assert(isim0(o));
  return (long)((((o >> 2) & 0x3fffffff) ^ 0x20000000) - 0x20000000);
}
long getimmu(obj o, int t) {
  assert(isimm(o, t));
  return (long)((o >> 8) & 0xffffff);
}
#endif")

(%definition "#define mkim0(o) (obj)((((o) & 0x3fffffff) << 2) | 3)")
(%definition "#define mkimm(o, t) (obj)((((o) & 0xffffff) << 8) | ((t) << 2) | 1)")



; native blocks are 1-element blocks containing a native
; (non-cx) pointer as 0th element and cxtype ptr in block header

(%localdef "#ifndef NDEBUG
int isnative(obj o, cxtype_t *tp) {
  return isobjptr(o) && objptr_from_obj(o)[-1] == (obj)tp; 
}
void *getnative(obj o, cxtype_t *tp) {
  assert(isnative(o, tp));
  return (void*)(*objptr_from_obj(o));
}
#endif")

(%definition "#ifdef NDEBUG
   static int isnative(obj o, cxtype_t *tp) 
     { return isobjptr(o) && objptr_from_obj(o)[-1] == (obj)tp;  }
   #define getnative(o, t) ((void*)(*objptr_from_obj(o)))
#else
  extern int isnative(obj o, cxtype_t *tp);
  extern void *getnative(obj o, cxtype_t *tp);
#endif")



; tagged blocks are heap blocks with runtime int tag as 0th element
; (disjoint from closures which have a foreign pointer as 0th element
; and from typed blocks which have scheme heap pointer as 0th element)

(%definition "extern int istagged(obj o, int t);")
(%localdef "int istagged(obj o, int t) {
  if (!isobjptr(o)) return 0;
  else { obj h = objptr_from_obj(o)[-1];
    return notaptr(h) && size_from_obj(h) >= 1 
      && hblkref(o, 0) == obj_from_size(t); }
}")

(%definition "#ifdef NDEBUG
  #define cktagged(o, t) (o)
  #define taggedlen(o, t) (hblklen(o)-1) 
  #define taggedref(o, t, i) (&hblkref(o, (i)+1))
#else
  extern obj cktagged(obj o, int t);
  extern int taggedlen(obj o, int t);
  extern obj* taggedref(obj o, int t, int i); 
#endif")
(%localdef "#ifndef NDEBUG
obj cktagged(obj o, int t) {
  assert(istagged(o, t));
  return o;
}
int taggedlen(obj o, int t) {
  assert(istagged(o, t));
  return hblklen(o) - 1;
}
obj* taggedref(obj o, int t, int i) {
  int len; assert(istagged(o, t));
  len = hblklen(o);
  assert(i >= 0 && i < len-1);  
  return &hblkref(o, i+1);
}
#endif")



; typed blocks have non-immediate scheme tag as 0th element
; (disjoint from closures and native/tagged blocks)

(%definition "extern int istyped(obj o);")
(%localdef "int istyped(obj o) {
  if (!isobjptr(o)) return 0;
  else { obj h = objptr_from_obj(o)[-1];
    return notaptr(h) && size_from_obj(h) >= 1 
      && isobjptr(hblkref(o, 0)); }
}")

(%definition "#ifdef NDEBUG
  #define cktyped(o, t) (o)
  #define typedtype(o) (&hblkref(o, 0))
  #define typedlen(o) (hblklen(o)-1) 
  #define typedref(o, i) (&hblkref(o, (i)+1))
#else
  extern obj cktyped(obj o);
  extern obj* typedtype(obj o); 
  extern int typedlen(obj o);
  extern obj* typedref(obj o, int i); 
#endif")
(%localdef "#ifndef NDEBUG
obj cktyped(obj o) {
  assert(istyped(o));
  return o;
}
obj* typedtype(obj o) {
  assert(istyped(o));
  return &hblkref(o, 0);
}
int typedlen(obj o) {
  assert(istyped(o));
  return hblklen(o) - 1;
}
obj* typedref(obj o, int i) {
  int len; assert(istyped(o));
  len = hblklen(o);
  assert(i >= 0 && i < len-1);  
  return &hblkref(o, i+1);
}
#endif")



; booleans

; #f is (obj)0, #t is immediate 0 with tag 0 (singular true object)
; this layout is compatible with C conventions (0 = false, 1 = true)
; note that any obj but #f is counted as true in conditionals and that
; bool_from_obj and bool_from_bool are already defined in std prelude


(%definition "/* booleans */")
(%definition "#define TRUE_ITAG 0")  
(%definition "typedef int bool_t;")
(%definition "#define is_bool_obj(o) (!((o) & ~(obj)1))")  
(%definition "#define is_bool_bool(b) ((void)(b), 1)")  
(%definition "#define void_from_bool(b) (void)(b)")
(%definition "#define obj_from_bool(b) ((b) ? mkimm(0, TRUE_ITAG) : 0)")

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (boolean)
      [(_ boolean b) (%prim ("bool(" b ")"))] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (boolean? x)
  (%prim "bool(is_bool_$arg)" x))

(define-inline (not x)
  (%prim "bool(!bool_from_$arg)" x))

(define-syntax boolean=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(bool_from_$arg == bool_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (boolean=? x t) (boolean=? t z ...)))]
    [_ %residual-boolean=?]))



; void 

; void object redefined as immediate with payload 0 and immediate tag 1


(%definition "/* void */")
(%definition "#define VOID_ITAG 1")  
(%definition "#define mkvoid() mkimm(0, VOID_ITAG)")  
(%definition "#define isvoid(o) ((o) == mkimm(0, VOID_ITAG))")  
(%definition "#undef obj_from_void")
(%definition "#define obj_from_void(v) ((void)(v), mkimm(0, VOID_ITAG))")

(define-inline (void) (%prim "void(0)"))
(define-inline (void? x) (%prim "bool(obj_from_$arg == obj_from_void(0))" x))


; unit

; this is the value to be used when zero results are returned to a context
; where one result is expected; it is analogous to a 0-element tuple

(%definition "/* unit */")
(%definition "#define obj_from_unit() (obj_from_size(0x6DF6F577))")


; numerical helpers

(%definition "/* numbers */")
(%definition "#define FIXNUM_BIT 30")
(%definition "#define FIXNUM_MIN -536870912")
(%definition "#define FIXNUM_MAX 536870911")
(%definition "#ifdef NDEBUG
#define fxneg(x) (-(x))
#define fxabs(x) (labs(x))
#define fxadd(x, y) ((x) + (y))
#define fxsub(x, y) ((x) - (y))
#define fxmul(x, y) ((x) * (y))
/* exact integer division */
#define fxdiv(x, y) ((x) / (y))  
/* truncated division (common/C99) */
#define fxquo(x, y) ((x) / (y))  
#define fxrem(x, y) ((x) % (y))
/* floor division */
static long fxmqu(long x, long y) {
  long q = x / y; return ((x < 0 && y > 0) || (x > 0 && y < 0)) ? q - 1 : q;
}
static long fxmlo(long x, long y) {
  long r = x % y; return ((r < 0 && y > 0) || (r > 0 && y < 0)) ? r + y : r;
}
/* euclidean division */
static long fxeuq(long x, long y) { 
  long q = x / y, r = x % y; return (r < 0) ? ((y > 0) ? q - 1 : q + 1) : q;
}
static long fxeur(long x, long y) {
  long r = x % y; return (r < 0) ? ((y > 0) ? r + y : r - y) : r;
} 
static long fxgcd(long x, long y) {
  long a = labs(x), b = labs(y), c; while (b) c = a%b, a = b, b = c; 
  return a;
} 
#define fxasl(x, y) ((x) << (y))
#define fxasr(x, y) ((x) >> (y))
#define fxflo(f) ((long)(f))
#else
extern long fxneg(long x);
extern long fxabs(long x);
extern long fxadd(long x, long y);
extern long fxsub(long x, long y);
extern long fxmul(long x, long y);
extern long fxdiv(long x, long y);
extern long fxquo(long x, long y);
extern long fxrem(long x, long y);
extern long fxmqu(long x, long y);
extern long fxmlo(long x, long y);
extern long fxeuq(long x, long y);
extern long fxeur(long x, long y);
extern long fxgcd(long x, long y);
extern long fxasl(long x, long y);
extern long fxasr(long x, long y);
extern long fxflo(double f);
#endif")

(%localdef "#ifndef NDEBUG
long fxneg(long x) { 
  assert(x != FIXNUM_MIN); 
  return -x; 
}
long fxabs(long x) { 
  assert(x != FIXNUM_MIN); 
  return labs(x); 
}
long fxadd(long x, long y) { 
  long z = x + y; 
  assert(z >= FIXNUM_MIN && z <= FIXNUM_MAX); 
  return z; 
}
long fxsub(long x, long y) { 
  long z = x - y; 
  assert(z >= FIXNUM_MIN && z <= FIXNUM_MAX); 
  return z; 
}
long fxmul(long x, long y) { 
  double z = (double)x * (double)y;
  assert(z >= FIXNUM_MIN && z <= FIXNUM_MAX);
  return x * y; 
}
/* exact integer division */
long fxdiv(long x, long y) { 
  assert(y); 
  assert(x != FIXNUM_MIN || y != -1);
  assert(x % y == 0);
  return x / y; 
}
/* truncated division (common/C99) */
long fxquo(long x, long y) { 
  assert(y); assert(x != FIXNUM_MIN || y != -1);
  return x / y; 
}
long fxrem(long x, long y) { 
  assert(y);
  return x % y; 
}
/* floor division */
long fxmqu(long x, long y) {
  long q; assert(y); assert(x != FIXNUM_MIN || y != -1);
  q = x / y;
  return ((x < 0 && y > 0) || (x > 0 && y < 0)) ? q - 1 : q;
}
long fxmlo(long x, long y) {
  long r; assert(y); r = x % y;
  return ((r < 0 && y > 0) || (r > 0 && y < 0)) ? r + y : r;
}
/* euclidean division */
long fxeuq(long x, long y) { 
  long q, r; assert(y); assert(x != FIXNUM_MIN || y != -1);
  q = x / y, r = x % y; 
  return (r < 0) ? ((y > 0) ? q - 1 : q + 1) : q;
}
long fxeur(long x, long y) {
  long r; assert(y); r = x % y; 
  return (r < 0) ? ((y > 0) ? r + y : r - y) : r;
} 
long fxgcd(long x, long y) {
  long a = labs(x), b = labs(y), c; 
  while (b) c = a%b, a = b, b = c; 
  assert(a <= FIXNUM_MAX);
  return a;
} 
long fxasl(long x, long y) {
  assert(y >= 0 && y < FIXNUM_BIT); 
  return x << y;
} 
long fxasr(long x, long y) {
  assert(y >= 0 && y < FIXNUM_BIT);
  assert(!y || x >= 0); /* >> of negative x is undefined */ 
  return x >> y;
} 
long fxflo(double f) {
  long l = (long)f; assert((double)l == f);
  assert(l >= FIXNUM_MIN && l <= FIXNUM_MAX);
  return l;
}
#endif")

(%definition "static int flisint(double f) { return f > -HUGE_VAL && f < HUGE_VAL && f == floor(f); }")

(%definition "extern long fxpow(long x, long y);")
(%localdef "long fxpow(long x, long y) { 
  assert(y >= 0);
  retry: if (y == 0) return 1; if (y == 1) return x;
  if (y % 2 == 1) x *= fxpow(x, y-1); 
  else { x *= x; y /= 2; assert(FIXNUM_MIN <= x && x <= FIXNUM_MAX); goto retry; }
  assert(FIXNUM_MIN <= x && x <= FIXNUM_MAX); return x;
}")

(%definition "extern long fxsqrt(long x);")
(%localdef "long fxsqrt(long x) { 
  assert(x >= 0); if (x < 2) return x;
  else { long s = fxsqrt(x >> 2) << 1, l = s + 1; return l*l > x ? s : l; }
}")

(%definition "extern int fxifdv(long x, long y, long *pi, double *pd);")
(%localdef "int fxifdv(long x, long y, long *pi, double *pd) { 
  assert(y); assert(x != FIXNUM_MIN || y != -1);
  if (x % y == 0) { *pi = x / y; return 1; }
  else { *pd = (double)x / (double)y; return 0; }  
}")

(%definition "extern double flquo(double x, double y);")
(%localdef "double flquo(double x, double y) {
  double z; assert(y != 0.0 && flisint(x) && flisint(y));
  modf(x / y,  &z);
  return z;
}")
(%definition "extern double flrem(double x, double y);")
(%localdef "double flrem(double x, double y) {
  assert(y != 0.0 && flisint(x) && flisint(y));
  return fmod(x, y);
}")
(%definition "extern double flmqu(double x, double y);")
(%localdef "double flmqu(double x, double y) {
  assert(y != 0.0 && flisint(x) && flisint(y));
  return floor(x / y);
}")
(%definition "extern double flmlo(double x, double y);")
(%localdef "double flmlo(double x, double y) {
  assert(y != 0.0 && flisint(x) && flisint(y));
  return x - y * floor(x / y);
}")
(%definition "extern double flgcd(double x, double y);")
(%localdef "double flgcd(double x, double y) {
  double a = fabs(x), b = fabs(y), c; 
  assert(flisint(a) && flisint(b));
  while (b > 0.0) c = fmod(a, b), a = b, b = c; 
  return a;
}")
(%definition "extern double flround(double x);")
(%localdef "double flround(double x) {
  double f = floor(x), c = ceil(x), d = x-f, u = c-x; 
  if (d == u) return fmod(f, 2.0) == 0.0 ? f : c;
  else return (d < u) ? f : c;
}")
(%definition "extern int strtofxfl(char *s, int radix, long *pl, double *pd);")
(%localdef "int strtofxfl(char *s, int radix, long *pl, double *pd) {
  extern int strcmp_ci(char *s1, char *s2); /* defined below */
  char *e; int conv = 0, eno = errno; long l; double d;
  for (; s[0] == '#'; s += 2) {
    switch (s[1]) {
      case 'b': case 'B': radix = 2; break;
      case 'o': case 'O': radix = 8; break;
      case 'd': case 'D': radix = 10; break;
      case 'x': case 'X': radix = 16; break;
      case 'e': case 'E': conv = 'e'; break;
      case 'i': case 'I': conv = 'i'; break;
      default: return 0;
    }
  }
  if (isspace(*s)) return 0;
  for (e = s; *e; ++e) { if (strchr(\".eEiInN\", *e)) break; }
  if (!*e || radix != 10) { /* s is not a syntax for an inexact number */
    l = (errno = 0, strtol(s, &e, radix));
    if (errno || *e || e == s) { if (conv == 'i') goto fl; return (errno = eno, 0); }
    if (conv == 'i') return (errno = eno, *pd = (double)l, 'i');
    if (FIXNUM_MIN <= l && l <= FIXNUM_MAX) return (errno = eno, *pl = l, 'e');
    return (errno = eno, 0); /* can't represent as an exact */
  } 
  fl: if (radix != 10) return (errno = eno, 0); 
  e = \"\", errno = 0; if (*s != '+' && *s != '-') d = strtod(s, &e);
  else if (strcmp_ci(s+1, \"inf.0\") == 0) d = (*s == '-' ? -HUGE_VAL : HUGE_VAL); 
  else if (strcmp_ci(s+1, \"nan.0\") == 0) d = HUGE_VAL - HUGE_VAL;
  else d = strtod(s, &e);
  if (errno || *e || e == s) return (errno = eno, 0);
  if ((conv == 'e') && ((l=(long)d) < FIXNUM_MIN || l > FIXNUM_MAX || (double)l != d))
    return (errno = eno, 0); /* can't be converted to an exact number */
  return (errno = eno, (conv == 'e') ? (*pl = fxflo(d), 'e') : (*pd = d, 'i'));
}")



; fixnums

; fixnums are tag-less immediates with 30 bits of payload

(%definition "/* fixnums */")
(%definition "typedef long fixnum_t;")
(%definition "#define is_fixnum_obj(o) (isim0(o))")
(%definition "#define is_fixnum_fixnum(i) ((void)(i), 1)")
(%definition "#define is_bool_fixnum(i) ((void)(i), 0)")
(%definition "#define is_fixnum_bool(i) ((void)(i), 0)")
(%definition "#define fixnum_from_obj(o) (getim0s(o))")
(%definition "#define fixnum_from_fixnum(i) (i)")
(%definition "#define fixnum_from_flonum(l,x) ((fixnum_t)(x))")
(%definition "#define bool_from_fixnum(i) ((void)(i), 1)")
(%definition "#define void_from_fixnum(i) (void)(i)")
(%definition "#define obj_from_fixnum(i) mkim0((fixnum_t)(i))")

(define-syntax %const
  (let-syntax ([old-%const %const])
    (letrec-syntax
       ([bin->oct
         (syntax-rules ()
           [(_ b sign digs) (bin->oct b sign #&(string->list digs) ())]
           [(_ b sign () l) (%const integer b sign #&(list->string l) 8)]
           [(_ b sign (#\0) l) (bin->oct b sign () (#\0 . l))] 
           [(_ b sign (#\1) l) (bin->oct b sign () (#\1 . l))]    
           [(_ b sign (#\0 #\0) l) (bin->oct b sign () (#\0 . l))] 
           [(_ b sign (#\0 #\1) l) (bin->oct b sign () (#\1 . l))]    
           [(_ b sign (#\1 #\0) l) (bin->oct b sign () (#\2 . l))] 
           [(_ b sign (#\1 #\1) l) (bin->oct b sign () (#\3 . l))]    
           [(_ b sign (d ... #\0 #\0 #\0) l) (bin->oct b sign (d ...) (#\0 . l))] 
           [(_ b sign (d ... #\0 #\0 #\1) l) (bin->oct b sign (d ...) (#\1 . l))] 
           [(_ b sign (d ... #\0 #\1 #\0) l) (bin->oct b sign (d ...) (#\2 . l))] 
           [(_ b sign (d ... #\0 #\1 #\1) l) (bin->oct b sign (d ...) (#\3 . l))] 
           [(_ b sign (d ... #\1 #\0 #\0) l) (bin->oct b sign (d ...) (#\4 . l))] 
           [(_ b sign (d ... #\1 #\0 #\1) l) (bin->oct b sign (d ...) (#\5 . l))] 
           [(_ b sign (d ... #\1 #\1 #\0) l) (bin->oct b sign (d ...) (#\6 . l))] 
           [(_ b sign (d ... #\1 #\1 #\1) l) (bin->oct b sign (d ...) (#\7 . l))])])   
      (syntax-rules (integer exact inexact)
        [(_ integer 8 sign digs 2) (bin->oct 8 sign digs)] 
        [(_ integer 16 sign digs 2) (bin->oct 16 sign digs)] 
        [(_ integer 24 sign digs 2) (bin->oct 24 sign digs)] 
        [(_ integer 8 sign digs 8) (%prim ("fixnum(" #&(id->string sign) "0" digs ")"))] 
        [(_ integer 16 sign digs 8) (%prim ("fixnum(" #&(id->string sign) "0" digs ")"))] 
        [(_ integer 24 sign digs 8) (%prim ("fixnum(" #&(id->string sign) "0" digs ")"))] 
        [(_ integer 8 sign digs 10) (%prim ("fixnum(" #&(id->string sign) digs ")"))] 
        [(_ integer 16 sign digs 10) (%prim ("fixnum(" #&(id->string sign) digs ")"))] 
        [(_ integer 24 sign digs 10) (%prim ("fixnum(" #&(id->string sign) digs ")"))] 
        [(_ integer 8 sign digs 16) (%prim ("fixnum(" #&(id->string sign) "0x" digs ")"))] 
        [(_ integer 16 sign digs 16) (%prim ("fixnum(" #&(id->string sign) "0x" digs ")"))] 
        [(_ integer 24 sign digs 16) (%prim ("fixnum(" #&(id->string sign) "0x" digs ")"))]
        [(_ exact (integer . r)) (%const integer . r)] 
        [(_ inexact (integer . r)) (exact->inexact (%const integer . r))] 
        [(_ arg ...) (old-%const arg ...)])))) 

(define-inline (fixnum? x)
  (%prim "bool(is_fixnum_$arg)" x))

(define-inline (fixnum-width)
  (%prim "fixnum(FIXNUM_BIT)"))
  
(define-inline (least-fixnum)
  (%prim "fixnum(FIXNUM_MIN)"))

(define-inline (greatest-fixnum)
  (%prim "fixnum(FIXNUM_MAX)"))

(define-syntax fx=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(fixnum_from_$arg == fixnum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fx=? x t) (fx=? t z ...)))]
    [_ %residual-fx=?]))

(define-syntax fx<?
  (syntax-rules ()
    [(_ x y) (%prim "bool(fixnum_from_$arg < fixnum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fx<? x t) (fx<? t z ...)))]
    [_ %residual-fx<?]))

(define-syntax fx>?
  (syntax-rules ()
    [(_ x y) (%prim "bool(fixnum_from_$arg > fixnum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fx>? x t) (fx>? t z ...)))]
    [_ %residual-fx>?]))

(define-syntax fx<=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(fixnum_from_$arg <= fixnum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fx<=? x t) (fx<=? t z ...)))]
    [_ %residual-fx<=?]))

(define-syntax fx>=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(fixnum_from_$arg >= fixnum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fx>=? x t) (fx>=? t z ...)))]
    [_ %residual-fx>=?]))

(define-inline (fxzero? x)
  (%prim "bool(fixnum_from_$arg == 0)" x))

(define-inline (fxpositive? x)
  (%prim "bool(fixnum_from_$arg > 0)" x))

(define-inline (fxnegative? x)
  (%prim "bool(fixnum_from_$arg < 0)" x))

(define-inline (fxodd? x)
  (%prim "bool((fixnum_from_$arg & 1) != 0)" x))

(define-inline (fxeven? x)
  (%prim "bool((fixnum_from_$arg & 1) == 0)" x))

(define-syntax fxmax
  (syntax-rules ()
    [(_ x) x]
    [(_ x y) (let ([a x] [b y]) (if (fx>? a b) a b))]
    [(_ x y z ...) (fxmax (fxmax x y) z ...)]
    [_ %residual-fxmax]))

(define-syntax fxmin
  (syntax-rules ()
    [(_ x) x]
    [(_ x y) (let ([a x] [b y]) (if (fx<? a b) a b))]
    [(_ x y z ...) (fxmin (fxmin x y) z ...)]
    [_ %residual-fxmin]))

(define-syntax fx+
  (syntax-rules ()
    [(_) (%prim "fixnum(0)")] [(_ x) x]
    [(_ x y) (%prim "fixnum(fxadd(fixnum_from_$arg, fixnum_from_$arg))" x y)]
    [(_ x y z ...) (fx+ x (fx+ y z ...))]
    [_ %residual-fx+]))

(define-syntax fx*
  (syntax-rules ()
    [(_) (%prim "fixnum(1)")] [(_ x) x]
    [(_ x y) (%prim "fixnum(fxmul(fixnum_from_$arg, fixnum_from_$arg))" x y)]
    [(_ x y z ...) (fx* x (fx* y z ...))]
    [_ %residual-fx*]))

(define-syntax fx-
  (syntax-rules ()
    [(_ x) (%prim "fixnum(fxneg(fixnum_from_$arg))" x)]
    [(_ x y) (%prim "fixnum(fxsub(fixnum_from_$arg, fixnum_from_$arg))" x y)]
    [(_ x y z ...) (fx- (fx- x y) z ...)]
    [_ %residual-fx-]))

(define-syntax fx/
  (syntax-rules ()
    [(_ x) (%prim "fixnum(fxdiv(1, fixnum_from_$arg))" x)]
    [(_ x y) (%prim "fixnum(fxdiv(fixnum_from_$arg, fixnum_from_$arg))" x y)]
    [(_ x y z ...) (fx/ (fx/ x y) z ...)]
    [_ %residual-fx/]))

(define-inline (fxquotient x y)
  (%prim "fixnum(fxquo(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxremainder x y)
  (%prim "fixnum(fxrem(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxmodquo x y)
  (%prim "fixnum(fxmqu(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxmodulo x y)
  (%prim "fixnum(fxmlo(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxeuq x y)
  (%prim "fixnum(fxeuq(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxeur x y)
  (%prim "fixnum(fxeur(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxabs x)
  (%prim "fixnum(fxabs(fixnum_from_$arg))" x))

(define-inline (fxgcd x y)
  (%prim "fixnum(fxgcd(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxexpt x y)
  (%prim* "fixnum(fxpow(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxsqrt x)
  (%prim "fixnum(fxsqrt(fixnum_from_$arg))" x))
  
(define-inline (fxnot x)
  (%prim "fixnum(~fixnum_from_$arg)" x))
  
(define-inline (fxand x y)
  (%prim "fixnum(fixnum_from_$arg & fixnum_from_$arg)" x y))
  
(define-inline (fxior x y)
  (%prim "fixnum(fixnum_from_$arg | fixnum_from_$arg)" x y))

(define-inline (fxxor x y)
  (%prim "fixnum(fixnum_from_$arg ^ fixnum_from_$arg)" x y))

(define-inline (fxarithmetic-shift-left x y)
  (%prim "fixnum(fxasl(fixnum_from_$arg, fixnum_from_$arg))" x y))

(define-inline (fxarithmetic-shift-right x y)
  (%prim "fixnum(fxasr(fixnum_from_$arg, fixnum_from_$arg))" x y))


; flonums

(%include <math.h>)
(%include <errno.h>)

(%definition "/* flonums */")
(%localdef "static cxtype_t cxt_flonum = { \"flonum\", free };")
(%localdef "cxtype_t *FLONUM_NTAG = &cxt_flonum;")
(%definition "extern cxtype_t *FLONUM_NTAG;")
(%definition "typedef double flonum_t;")
(%definition "#define is_flonum_obj(o) (isnative(o, FLONUM_NTAG))")
(%definition "#define is_flonum_flonum(f) ((void)(f), 1)")
(%definition "#define is_flonum_bool(f) ((void)(f), 0)")
(%definition "#define is_bool_flonum(f) ((void)(f), 0)")
(%definition "#define is_fixnum_flonum(i) ((void)(i), 0)")
(%definition "#define is_flonum_fixnum(i) ((void)(i), 0)")
(%definition "#define flonum_from_obj(o) (*(flonum_t*)getnative(o, FLONUM_NTAG))")
(%definition "#define flonum_from_flonum(l, f) (f)")
(%definition "#define flonum_from_fixnum(x) ((flonum_t)(x))")
(%definition "#define bool_from_flonum(f) ((void)(f), 0)")
(%definition "#define void_from_flonum(l, f) (void)(f)")
(%definition "#define obj_from_flonum(l, f) hpushptr(dupflonum(f), FLONUM_NTAG, l)")
(%definition "extern flonum_t *dupflonum(flonum_t f);")
(%localdef "flonum_t *dupflonum(flonum_t f) {
  flonum_t *pf = cxm_cknull(malloc(sizeof(flonum_t)), \"malloc(flonum)\");
  *pf = f; return pf;
}")

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (decimal e exact inexact inf nan)
      [(_ decimal e str) 
       (%prim* ("flonum($live, " str ")"))]
      [(_ decimal e ms indigs frdigs es exdigs) 
       (%prim* ("flonum($live, " #&(id->string ms) 
         indigs "." frdigs "e" #&(id->string es) exdigs ")"))]
      [(_ inexact (decimal . r)) (%const decimal . r)]
      [(_ exact (decimal . r)) (inexact->exact (%const decimal . r))] 
      [(_ inf ms) (%prim* ("flonum($live, " #&(id->string ms) "HUGE_VAL)"))]
      [(_ inexact (inf . r)) (%const inf . r)] 
      [(_ nan ms) (%prim* ("flonum($live, HUGE_VAL-HUGE_VAL)"))]
      [(_ inexact (nan . r)) (%const nan . r)] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (flonum? x)
  (%prim "bool(is_flonum_$arg)" x))

(define-inline (fixnum->flonum n) 
  (%prim* "flonum($live, (flonum_t)fixnum_from_$arg)" n))

(define-inline (flonum->fixnum x) 
  (%prim "fixnum(fxflo(flonum_from_$arg))" x))

(define-inline (real->flonum n)
  (if (flonum? n) n (fixnum->flonum n))) 

(define-inline (real->fixnum n)
  (if (fixnum? n) n (flonum->fixnum n))) 

(define-syntax fl=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(flonum_from_$arg == flonum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fl=? x t) (fl=? t z ...)))]
    [_ %residual-fl=?]))

(define-syntax fl<?
  (syntax-rules ()
    [(_ x y) (%prim "bool(flonum_from_$arg < flonum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fl<? x t) (fl<? t z ...)))]
    [_ %residual-fl<?]))

(define-syntax fl>?
  (syntax-rules ()
    [(_ x y) (%prim "bool(flonum_from_$arg > flonum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fl>? x t) (fl>? t z ...)))]
    [_ %residual-fl>?]))

(define-syntax fl<=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(flonum_from_$arg <= flonum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fl<=? x t) (fl<=? t z ...)))]
    [_ %residual-fl<=?]))

(define-syntax fl>=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(flonum_from_$arg >= flonum_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (fl>=? x t) (fl>=? t z ...)))]
    [_ %residual-fl>=?]))

(define-inline (flinteger? x)
  (%prim "bool(flisint(flonum_from_$arg))" x))

(define-inline (flzero? x)
  (%prim "bool(flonum_from_$arg == 0.0)" x))

(define-inline (flpositive? x)
  (%prim "bool(flonum_from_$arg > 0.0)" x))

(define-inline (flnegative? x)
  (%prim "bool(flonum_from_$arg < 0.0)" x))

(define-inline (flodd? x)
  (%prim "bool(flisint((flonum_from_$arg + 1.0) / 2.0))" x))
 
(define-inline (fleven? x)
  (%prim "bool(flisint(flonum_from_$arg / 2.0))" x))

(define-inline (flnan? x)
  (%prim "{ /* flnan? */ 
    flonum_t f = flonum_from_$arg;
    $return bool(f != f); }" x))

(define-inline (flinfinite? x)
  (%prim "{ /* flinfinite? */ 
    flonum_t f = flonum_from_$arg;
    $return bool(f <= -HUGE_VAL || f >= HUGE_VAL); }" x))

(define-syntax flmax
  (syntax-rules ()
    [(_ x) x]
    [(_ x y) (let ([a x] [b y]) (if (fl>? a b) a b))]
    [(_ x y z ...) (flmax (flmax x y) z ...)]
    [_ %residual-flmax]))

(define-syntax flmin
  (syntax-rules ()
    [(_ x) x]
    [(_ x y) (let ([a x] [b y]) (if (fl<? a b) a b))]
    [(_ x y z ...) (flmin (flmin x y) z ...)]
    [_ %residual-flmin]))

(define-syntax fl+
  (syntax-rules ()
    [(_) (%prim* "flonum($live, 0.0)")] [(_ x) x]
    [(_ x y) (%prim* "flonum($live, flonum_from_$arg + flonum_from_$arg)" x y)]
    [(_ x y z ...) (fl+ x (fl+ y z ...))]
    [_ %residual-fl+]))

(define-syntax fl*
  (syntax-rules ()
    [(_) (%prim* "flonum($live, 1.0)")] [(_ x) x]
    [(_ x y) (%prim* "flonum($live, flonum_from_$arg * flonum_from_$arg)" x y)]
    [(_ x y z ...) (fl* x (fl* y z ...))]
    [_ %residual-fl*]))

(define-syntax fl-
  (syntax-rules ()
    [(_ x) (%prim* "flonum($live, -flonum_from_$arg)" x)]
    [(_ x y) (%prim* "flonum($live, flonum_from_$arg - flonum_from_$arg)" x y)]
    [(_ x y z ...) (fl- (fl- x y) z ...)]
    [_ %residual-fl-]))

(define-syntax fl/
  (syntax-rules ()
    [(_ x) (%prim* "flonum($live, 1.0/flonum_from_$arg)" x)]
    [(_ x y) (%prim* "flonum($live, flonum_from_$arg / flonum_from_$arg)" x y)]
    [(_ x y z ...) (fl/ (fl/ x y) z ...)]
    [_ %residual-fl/]))

(define-inline (flquotient x y)
  (%prim* "flonum($live, flquo(flonum_from_$arg, flonum_from_$arg))" x y))

(define-inline (flremainder x y)
  (%prim* "flonum($live, flrem(flonum_from_$arg, flonum_from_$arg))" x y))

(define-inline (flmodquo x y)
  (%prim* "flonum($live, flmqu(flonum_from_$arg, flonum_from_$arg))" x y))

(define-inline (flmodulo x y)
  (%prim* "flonum($live, flmlo(flonum_from_$arg, flonum_from_$arg))" x y))

(define-inline (flabs x)
  (%prim* "flonum($live, fabs(flonum_from_$arg))" x))

(define-inline (flgcd x y)
  (%prim* "flonum($live, flgcd(flonum_from_$arg, flonum_from_$arg))" x y))

(define-inline (flfloor x)
  (%prim* "flonum($live, floor(flonum_from_$arg))" x))

(define-inline (flceiling x)
  (%prim* "flonum($live, ceil(flonum_from_$arg))" x))

(define-inline (fltruncate x)
  (%prim* "{ /* fltruncate */ 
    flonum_t x = flonum_from_$arg;
    double i; modf(x,  &i);
    $return flonum($live, i); }" x))
    
(define-inline (flround x)
  (%prim* "flonum($live, flround(flonum_from_$arg))" x))

(define-inline (flsqrt x)
  (%prim* "flonum($live, sqrt(flonum_from_$arg))" x))

(define-inline (flexp x)
  (%prim* "flonum($live, exp(flonum_from_$arg))" x))

(define-inline (fllog x)
  (%prim* "flonum($live, log(flonum_from_$arg))" x))

(define-inline (fllog10 x)
  (%prim* "flonum($live, log10(flonum_from_$arg))" x))

(define-inline (flsin x)
  (%prim* "flonum($live, sin(flonum_from_$arg))" x))

(define-inline (flcos x)
  (%prim* "flonum($live, cos(flonum_from_$arg))" x))

(define-inline (fltan x)
  (%prim* "flonum($live, tan(flonum_from_$arg))" x))

(define-inline (flasin x)
  (%prim* "flonum($live, asin(flonum_from_$arg))" x))

(define-inline (flacos x)
  (%prim* "flonum($live, acos(flonum_from_$arg))" x))

(define-syntax flatan
  (syntax-rules ()
    [(_ x) (%prim* "flonum($live, atan(flonum_from_$arg))" x)]
    [(_ y x) (%prim* "flonum($live, atan2(flonum_from_$arg, flonum_from_$arg))" y x)]
    [_ %residual-flatan]))

(define-inline (flexpt x y)
  (%prim* "flonum($live, pow(flonum_from_$arg, flonum_from_$arg))" x y))

(define-inline (fxfl/ x y)
  (%prim* "{ /* fxfl/ */ 
    fixnum_t x = fixnum_from_$arg, y = fixnum_from_$arg;
    long i; double d;
    if (0) $return obj(0); /* to fool sfc unboxer */
    else if (fxifdv(x, y, &i, &d)) $return fixnum(i);
    else $return flonum($live, d); }" x y))


; generic math (fixnum/flonum)

(define-inline (real? x)
  (or (fixnum? x) (flonum? x))) 

(define-inline (integer? x)
  (or (fixnum? x) (and (flonum? x) (flinteger? x)))) 

(define-syntax exact-integer? fixnum?)

(define-inline rational? integer?)
(define-inline complex? real?)
(define-inline number? real?)

(define-inline exact? fixnum?)
(define-inline inexact? flonum?)
(define-inline (exact x)
  (if (fixnum? x) x (flonum->fixnum x)))
(define-inline (inexact x)
  (if (flonum? x) x (fixnum->flonum x)))
(define-syntax inexact->exact exact)
(define-syntax exact->inexact inexact)

(define-syntax real-binop
  (syntax-rules ()
    [(_ x y fxop flop) 
     (let ([a x] [b y])
       (if (fixnum? a)
           (if (fixnum? b)
               (fxop a b)
               (flop (fixnum->flonum a) b))
           (if (fixnum? b)
               (flop a (fixnum->flonum b))
               (flop a b))))]))

(define-syntax =
  (syntax-rules ()
    [(_ x y) (real-binop x y fx=? fl=?)] 
    [(_ x y z ...) (let ([t y]) (and (= x t) (= t z ...)))]
    [_ %residual=]))

(define-syntax <
  (syntax-rules ()
    [(_ x y) (real-binop x y fx<? fl<?)]
    [(_ x y z ...) (let ([t y]) (and (< x t) (< t z ...)))]
    [_ %residual<]))

(define-syntax >
  (syntax-rules ()
    [(_ x y) (real-binop x y fx>? fl>?)]
    [(_ x y z ...) (let ([t y]) (and (> x t) (> t z ...)))]
    [_ %residual>]))

(define-syntax <=
  (syntax-rules ()
    [(_ x y) (real-binop x y fx<=? fl<=?)]
    [(_ x y z ...) (let ([t y]) (and (<= x t) (<= t z ...)))]
    [_ %residual<=]))

(define-syntax >=
  (syntax-rules ()
    [(_ x y) (real-binop x y fx>=? fl>=?)]
    [(_ x y z ...) (let ([t y]) (and (>= x t) (>= t z ...)))]
    [_ %residual>=]))

(define-inline (zero? x)
  (if (fixnum? x) (fxzero? x) (flzero? x))) 

(define-inline (positive? x)
  (if (fixnum? x) (fxpositive? x) (flpositive? x))) 

(define-inline (negative? x)
  (if (fixnum? x) (fxnegative? x) (flnegative? x))) 

(define-inline (even? x)
  (if (fixnum? x) (fxeven? x) (fleven? x))) 

(define-inline (odd? x)
  (if (fixnum? x) (fxodd? x) (flodd? x)))

(define-inline (nan? x)
  (and (flonum? x) (flnan? x))) 

(define-inline (infinite? x)
  (and (flonum? x) (flinfinite? x))) 

(define-inline (finite? x)
  (or (fixnum? x) (not (flinfinite? x)))) 

(define-syntax max
  (syntax-rules ()
    [(_ x) x]
    [(_ x y) 
     (let ([a x] [b y]) 
       (if (and (fixnum? a) (fixnum? b)) (if (fx>? a b) a b) (%residual-max/2 a b)))]
    [(_ x y z ...) (%residual-max x y z ...)]
    [_ %residual-max]))

(define-syntax min
  (syntax-rules ()
    [(_ x) x]
    [(_ x y)
     (let ([a x] [b y]) 
       (if (and (fixnum? a) (fixnum? b)) (if (fx<? a b) a b) (%residual-min/2 a b)))]
    [(_ x y z ...) (%residual-min x y z ...)]
    [_ %residual-min]))

(define-syntax +
  (syntax-rules ()
    [(_) 0] 
    [(_ x) x]
    [(_ x y) (real-binop x y fx+ fl+)]
    [(_ x y z ...) (+ (+ x y) z ...)]
    [_ %residual+]))

(define-syntax *
  (syntax-rules ()
    [(_) 1]
    [(_ x) x]
    [(_ x y) (real-binop x y fx* fl*)]
    [(_ x y z ...) (* (* x y) z ...)]
    [_ %residual*]))

(define-syntax -
  (syntax-rules ()
    [(_ x) (let ([a x]) (if (fixnum? a) (fx- a) (fl- a)))]
    [(_ x y) (real-binop x y fx- fl-)]
    [(_ x y z ...) (- (- x y) z ...)]
    [_ %residual-]))

(define-syntax /
  (syntax-rules ()
    [(_ x) (let ([a x]) (if (fixnum? a) (fxfl/ 1 a) (fl/ a)))]
    [(_ x y) (real-binop x y fxfl/ fl/)]
    [(_ x y z ...) (/ (/ x y) z ...)]
    [_ %residual/]))
   
(define-inline (abs x)
  (if (fixnum? x) (fxabs x) (flabs x)))

(define-inline (quotient x y)
  (real-binop x y fxquotient flquotient))

(define-inline (remainder x y)
  (real-binop x y fxremainder flremainder))

(define-syntax truncate-quotient quotient)
(define-syntax truncate-remainder remainder)

(define-inline (modquo x y)
  (real-binop x y fxmodquo flmodquo))

(define-inline (modulo x y)
  (real-binop x y fxmodulo flmodulo))

(define-syntax floor-quotient modquo)
(define-syntax floor-remainder modulo)

(define-syntax gcd
  (syntax-rules ()
    [(_) 0] 
    [(_ x) x]
    [(_ x y) (real-binop x y fxgcd flgcd)]
    [(_ x y z ...) (gcd (gcd x y) z ...)]
    [_ %residual-gcd]))

(define (lcm/2 x y)
  (let ([g (gcd x y)])
    (if (zero? g) g (* (quotient (abs x) g) (abs y)))))

(define-syntax lcm
  (syntax-rules ()
    [(_) 1] 
    [(_ x) x]
    [(_ x y) (lcm/2 x y)]
    [(_ x y z ...) (lcm (lcm/2 x y) z ...)]
    [_ %residual-lcm]))

; no div
; no mod  

(define-inline (numerator n)
  n)

(define-inline (denominator n)
  1)

(define-inline (rationalize n d)
  n)

(define-inline (floor x)
  (if (fixnum? x) x (flfloor x)))

(define-inline (ceiling x)
  (if (fixnum? x) x (flceiling x)))

(define-inline (truncate x)
  (if (fixnum? x) x (fltruncate x)))

(define-inline (round x)
  (if (fixnum? x) x (flround x)))

; need exact version?
(define-inline (sqrt x)
  (flsqrt (real->flonum x)))

(define-inline (exp x)
  (flexp (real->flonum x)))

(define-syntax log
  (syntax-rules ()
    [(_ x) (fllog (real->flonum x))]
    [(_ x b) (if (fx=? b 10) (fllog10 (real->flonum x)) (fl/ (log x) (log b)))]
    [_ %residual-log]))

(define-inline (sin x)
  (flsin (real->flonum x)))

(define-inline (cos x)
  (flcos (real->flonum x)))

(define-inline (tan x)
  (fltan (real->flonum x)))

(define-inline (asin x)
  (flasin (real->flonum x)))

(define-inline (acos x)
  (flacos (real->flonum x)))

(define-syntax atan
  (syntax-rules ()
    [(_ x) (flatan (real->flonum x))]
    [(_ y x) (flatan (real->flonum y) (real->flonum x))]
    [_ %residual-atan]))

(define-inline (expt x y)
  (if (and (fixnum? x) (fixnum? y) (fx>=? y 0))
      (fxexpt x y)
      (flexpt (real->flonum x) (real->flonum y))))

(define-inline (square x) (* x x))


; characters

(%include <ctype.h>)

; characters are 24-bit immediates with immediate tag 2

(%definition "/* characters */")
(%definition "#define CHAR_ITAG 2")  
(%definition "typedef int char_t;")
(%definition "#define ischar(o) (isimm(o, CHAR_ITAG))")
(%definition "#define is_char_obj(o) (isimm(o, CHAR_ITAG))")
(%definition "#define is_char_char(i) ((void)(i), 1)")
(%definition "#define is_char_bool(i) ((void)(i), 0)")
(%definition "#define is_bool_char(i) ((void)(i), 0)")
(%definition "#define is_char_fixnum(i) ((void)(i), 0)")
(%definition "#define is_fixnum_char(i) ((void)(i), 0)")
(%definition "#define is_char_flonum(i) ((void)(i), 0)")
(%definition "#define is_flonum_char(i) ((void)(i), 0)")
(%definition "#define char_from_obj(o) ((int)getimmu(o, CHAR_ITAG))")
(%definition "#define char_from_char(i) (i)")
(%definition "#define bool_from_char(i) ((void)(i), 1)")
(%definition "#define void_from_char(i) (void)(i)")
(%definition "#define obj_from_char(i) mkimm(i, CHAR_ITAG)")

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (char)
      [(_ char 8 c) (%prim ("char(" c ")"))]
      [(_ char cs) (%prim ("char('" cs "')"))] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (char? x)
  (%prim "bool(is_char_$arg)" x))

(define-syntax char=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(char_from_$arg == char_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (char=? x t) (char=? t z ...)))]
    [_ %residual-char=?]))

(define-syntax char>?
  (syntax-rules ()
    [(_ x y) (%prim "bool(char_from_$arg > char_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (char>? x t) (char>? t z ...)))]
    [_ %residual-char>?]))

(define-syntax char<?
  (syntax-rules ()
    [(_ x y) (%prim "bool(char_from_$arg < char_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (char<? x t) (char<? t z ...)))]
    [_ %residual-char<?]))

(define-syntax char>=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(char_from_$arg >= char_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (char>=? x t) (char>=? t z ...)))]
    [_ %residual-char>=?]))

(define-syntax char<=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(char_from_$arg <= char_from_$arg)" x y)]
    [(_ x y z ...) (let ([t y]) (and (char<=? x t) (char<=? t z ...)))]
    [_ %residual-char<=?]))

(define-syntax char-ci=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(tolower(char_from_$arg) == tolower(char_from_$arg))" x y)]
    [(_ x y z ...) (let ([t y]) (and (char-ci=? x t) (char-ci=? t z ...)))]
    [_ %residual-char-ci=?]))

(define-syntax char-ci>?
  (syntax-rules ()
    [(_ x y) (%prim "bool(tolower(char_from_$arg) > tolower(char_from_$arg))" x y)]
    [(_ x y z ...) (let ([t y]) (and (char-ci>? x t) (char-ci>? t z ...)))]
    [_ %residual-char-ci>?]))

(define-syntax char-ci<?
  (syntax-rules ()
    [(_ x y) (%prim "bool(tolower(char_from_$arg) < tolower(char_from_$arg))" x y)]
    [(_ x y z ...) (let ([t y]) (and (char-ci<? x t) (char-ci<? t z ...)))]
    [_ %residual-char-ci<?]))

(define-syntax char-ci>=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(tolower(char_from_$arg) >= tolower(char_from_$arg))" x y)]
    [(_ x y z ...) (let ([t y]) (and (char-ci>=? x t) (char-ci>=? t z ...)))]
    [_ %residual-char-ci>=?]))

(define-syntax char-ci<=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(tolower(char_from_$arg) <= tolower(char_from_$arg))" x y)]
    [(_ x y z ...) (let ([t y]) (and (char-ci<=? x t) (char-ci<=? t z ...)))]
    [_ %residual-char-ci<=?]))

(define-inline (char-alphabetic? x)
  (%prim "bool(isalpha(char_from_$arg))" x))

(define-inline (char-numeric? x)
  (%prim "bool(isdigit(char_from_$arg))" x))

(define-inline (char-whitespace? x)
  (%prim "bool(isspace(char_from_$arg))" x))

(define-inline (char-upper-case? x)
  (%prim "bool(isupper(char_from_$arg))" x))

(define-inline (char-lower-case? x)
  (%prim "bool(islower(char_from_$arg))" x))

(define-inline (char->integer x)
  (%prim "fixnum((fixnum_t)char_from_$arg)" x))

(define-inline (integer->char x)
  (%prim "char((char_t)fixnum_from_$arg)" x))

(define-inline (char-upcase x)
  (%prim "char(toupper(char_from_$arg))" x))

(define-inline (char-downcase x)
  (%prim "char(tolower(char_from_$arg))" x))

(define-syntax char-foldcase char-downcase)

(define-inline (digit-value x)
  (and (char<=? #\0 x #\9) (fx- (char->integer x) (%prim "fixnum('0')"))))


; strings

(%include <string.h>)

(%definition "/* strings */")
(%localdef "static cxtype_t cxt_string = { \"string\", free };")
(%localdef "cxtype_t *STRING_NTAG = &cxt_string;")
(%definition "extern cxtype_t *STRING_NTAG;")
(%definition "#define isstring(o) (isnative(o, STRING_NTAG))")
(%definition "#define stringdata(o) ((int*)getnative(o, STRING_NTAG))")
(%definition "#define sdatachars(d) ((char*)((d)+1))")
(%definition "#define stringlen(o) (*stringdata(o))")
(%definition "#define stringchars(o) ((char*)(stringdata(o)+1))")
(%definition "#define hpushstr(l, s) hpushptr(s, STRING_NTAG, l)")

(%localdef "char* stringref(obj o, int i) {
  int *d = stringdata(o); assert(i >= 0 && i < *d);  
  return sdatachars(d)+i;
}")

(%definition "#ifdef NDEBUG
  #define stringref(o, i) (stringchars(o)+(i))
#else
  extern char* stringref(obj o, int i);
#endif")

(%definition "extern int *newstring(char *s);")
(%localdef "int *newstring(char *s) {
  int l, *d; assert(s); l = (int)strlen(s); 
  d = cxm_cknull(malloc(sizeof(int)+l+1), \"malloc(string)\");
  *d = l; strcpy(sdatachars(d), s); return d;
}")

(%definition "extern int *newstringn(char *s, int n);")
(%localdef "int *newstringn(char *s, int n) {
  int *d; char *ns; assert(s); assert(n >= 0);
  d = cxm_cknull(malloc(sizeof(int)+n+1), \"malloc(stringn)\");
  *d = n; memcpy((ns = sdatachars(d)), s, n); ns[n] = 0; return d;
}")

(%definition "extern int *allocstring(int n, int c);")
(%localdef "int *allocstring(int n, int c) {
  int *d; char *s; assert(n+1 > 0); 
  d = cxm_cknull(malloc(sizeof(int)+n+1), \"malloc(string)\");
  *d = n; s = sdatachars(d); memset(s, c, n); s[n] = 0;
  return d;
}")

(%definition "extern int *substring(int *d, int from, int to);")
(%localdef "int *substring(int *d0, int from, int to) {
  int n = to-from, *d1; char *s0, *s1; assert(d0);
  assert(0 <= from && from <= to && to <= *d0); 
  d1 = cxm_cknull(malloc(sizeof(int)+n+1), \"malloc(string)\");
  *d1 = n; s0 = sdatachars(d0); s1 = sdatachars(d1); 
  memcpy(s1, s0+from, n); s1[n] = 0;
  return d1;
}")

(%definition "extern int *stringcat(int *d0, int *d1);")
(%localdef "int *stringcat(int *d0, int *d1) {
  int l0 = *d0, l1 = *d1, n = l0+l1; char *s0, *s1, *s;
  int *d = cxm_cknull(malloc(sizeof(int)+n+1), \"malloc(string)\");
  *d = n; s = sdatachars(d); s0 = sdatachars(d0); s1 = sdatachars(d1);
  memcpy(s, s0, l0); memcpy(s+l0, s1, l1); s[n] = 0;
  return d;
}")

(%definition "extern int *dupstring(int *d);")
(%localdef "int *dupstring(int *d0) {
  int n = *d0, *d1 = cxm_cknull(malloc(sizeof(int)+n+1), \"malloc(string)\");
  memcpy(d1, d0, sizeof(int)+n+1);
  return d1;
}")

(%definition "extern void stringfill(int *d, int c);")
(%localdef "void stringfill(int *d, int c) {
  int l = *d, i; char *s = sdatachars(d);
  for (i = 0; i < l; ++i) s[i] = c;
}")

(%definition "extern int strcmp_ci(char *s1, char *s2);")
(%localdef "int strcmp_ci(char *s1, char *s2) {
  int c1, c2, d;
  do { c1 = *s1++; c2 = *s2++; d = (unsigned)tolower(c1) - (unsigned)tolower(c2); } while (!d && c1 && c2);
  return d;
}")

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (string)
      [(_ string s)
       (%prim* ("obj(hpushstr($live, newstring(\"" s "\")))"))]
      [(_ string 8 c ...)
       (%prim* ("{ static char s[] = { " (c ", ") ... "0 };\n"
                "    $return obj(hpushstr($live, newstring(s))); }"))]
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (string? x)
  (%prim "bool(isstring(obj_from_$arg))" x))

(define-syntax make-string
  (syntax-rules ()
    [(_ k) (%prim* "obj(hpushstr($live, allocstring(fixnum_from_$arg, '?')))" k)]
    [(_ k c) (%prim* "obj(hpushstr($live, allocstring(fixnum_from_$arg, char_from_$arg)))" k c)]
    [_ %residual-make-string]))

(define-syntax string
  (syntax-rules ()
    [(_ c ...)
     (%prim* "{ /* string */
    obj o = hpushstr($live, allocstring($argc, ' '));
    unsigned char *s = (unsigned char *)stringchars(o);
    ${*s++ = (unsigned char)char_from_$arg;
    $}$return obj(o); }" c ...)]
    [_ %residual-string]))

(define-inline (string-length s)
  (%prim "fixnum(stringlen(obj_from_$arg))" s))

(define-inline (string-ref s k)
  (%prim? "char(*(unsigned char*)stringref(obj_from_$arg, fixnum_from_$arg))" s k))

(define-inline (string-set! s k c)
  (%prim! "void(*stringref(obj_from_$arg, fixnum_from_$arg) = char_from_$arg)" s k c))

(define-syntax string=?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) == 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string=? x t) (string=? t z ...)))]
    [_ %residual-string=?]))

(define-syntax string<?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) < 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string<? x t) (string<? t z ...)))]
    [_ %residual-string<?]))

(define-syntax string>?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) > 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string>? x t) (string>? t z ...)))]
    [_ %residual-string>?]))

(define-syntax string<=?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) <= 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string<=? x t) (string<=? t z ...)))]
    [_ %residual-string<=?]))

(define-syntax string>=?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) >= 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string>=? x t) (string>=? t z ...)))]
    [_ %residual-string>=?]))

(define-syntax string-ci=?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp_ci(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) == 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string-ci=? x t) (string-ci=? t z ...)))]
    [_ %residual-string-ci=?]))

(define-syntax string-ci<?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp_ci(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) < 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string-ci<? x t) (string-ci<? t z ...)))]
    [_ %residual-string-ci<?]))

(define-syntax string-ci>?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp_ci(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) > 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string-ci>? x t) (string-ci>? t z ...)))]
    [_ %residual-string-ci>?]))

(define-syntax string-ci<=?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp_ci(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) <= 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string-ci<=? x t) (string-ci<=? t z ...)))]
    [_ %residual-string-ci<=?]))

(define-syntax string-ci>=?
  (syntax-rules ()
    [(_ x y) (%prim? "bool(strcmp_ci(stringchars(obj_from_$arg), stringchars(obj_from_$arg)) >= 0)" x y)]
    [(_ x y z ...) (let ([t y]) (and (string-ci>=? x t) (string-ci>=? t z ...)))]
    [_ %residual-string-ci>=?]))

(define-inline (string-upcase s)
  (%prim*? "{ /* string-upcase */
    int *d = dupstring(stringdata(obj_from_$arg)); char *s;
    for (s = sdatachars(d); *s; ++s) *s = toupper(*s);
    $return obj(hpushstr($live, d)); }" s))

(define-inline (string-downcase s)
  (%prim*? "{ /* string-downcase */
    int *d = dupstring(stringdata(obj_from_$arg)); char *s;
    for (s = sdatachars(d); *s; ++s) *s = tolower(*s);
    $return obj(hpushstr($live, d)); }" s))

(define-syntax string-foldcase string-downcase)

(define-inline (substring s start end)
  (%prim*? "{ /* substring */
    int *d = substring(stringdata(obj_from_$arg), fixnum_from_$arg, fixnum_from_$arg);
    $return obj(hpushstr($live, d)); }" s start end))

(define-inline (%string-append s1 s2)
  (%prim*? "{ /* string-append */
    int *d = stringcat(stringdata(obj_from_$arg), stringdata(obj_from_$arg));
    $return obj(hpushstr($live, d)); }" s1 s2))

(define-syntax string-append
  (syntax-rules ()
    [(_) ""] [(_ x) x]
    [(_ x y) (%string-append x y)]
    [(_ x y z ...) (%string-append x (string-append y z ...))]
    [_ %residual-string-append]))

(define-inline (%string-copy s)
  (%prim*? "{ /* string-copy */
    int *d = dupstring(stringdata(obj_from_$arg));
    $return obj(hpushstr($live, d)); }" s))

(define (substring-copy! to at from start end)
  (let ([limit (fxmin end (fx+ start (fx- (string-length to) at)))])
    (if (fx<=? at start)
        (do ([i at (fx+ i 1)] [j start (fx+ j 1)]) 
          [(fx>=? j limit)]
          (string-set! to i (string-ref from j)))
        (do ([i (fx+ at (fx- end start 1)) (fx- i 1)] [j (fx- limit 1) (fx- j 1)])
          [(fx<? j start)]
          (string-set! to i (string-ref from j))))))

(define (substring-fill! str c start end)
  (do ([i start (fx+ i 1)]) [(fx>=? i end)] (string-set! str i c)))

(define-inline (%string-fill! s c)
  (%prim! "void(stringfill(stringdata(obj_from_$arg), char_from_$arg))" s c))

(define-inline (string-position c s)
  (%prim? "{ /* string-position */
    char *s = stringchars(obj_from_$arg), *p = strchr(s, char_from_$arg);
    if (p) $return fixnum(p-s); else $return bool(0); }" s c))


; vectors

(%definition "/* vectors */")
(%definition "#define VECTOR_BTAG 1")  
(%definition "#define isvector(o) istagged(o, VECTOR_BTAG)")  
(%definition "#define vectorref(v, i) *taggedref(v, VECTOR_BTAG, i)")  
(%definition "#define vectorlen(v) taggedlen(v, VECTOR_BTAG)")  

(define-inline (vector? o)
  (%prim "bool(isvector(obj_from_$arg))" o))

(define-inline (%new-vector n)
  (%prim* "{ /* new-vector */
    int c = fixnum_from_$arg;
    hreserve(hbsz(c+1), $live); /* $live live regs */
    hp -= c; memset(hp, 0, c * sizeof(obj));
    *--hp = obj_from_size(VECTOR_BTAG);
    $return obj(hendblk(c+1)); }" n))

(define-inline (%make-vector n i)
  (%prim* "{ /* make-vector */
    obj o; int i = 0, c = fixnum_from_$arg;
    hreserve(hbsz(c+1), $live); /* $live live regs */
    o = obj_from_$arg; /* gc-safe */
    while (i++ < c) *--hp = o;
    *--hp = obj_from_size(VECTOR_BTAG);
    $return obj(hendblk(c+1)); }" n i))

(define-syntax make-vector
  (syntax-rules ()
    [(_ n) (%new-vector n)]
    [(_ n i) (%make-vector n i)]
    [_ %residual-make-vector]))

(define-syntax vector
  (syntax-rules ()
    [(_ i ...)
     (%prim*/rev "{ /* vector */
    hreserve(hbsz($argc+1), $live); /* $live live regs */
    ${*--hp = obj_from_$arg;
    $}*--hp = obj_from_size(VECTOR_BTAG);
    $return obj(hendblk($argc+1)); }" i ...)]
    [_ %residual-vector]))

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (vector)
      [(_ vector x ...) (vector x ...)] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (vector-length v)
  (%prim "fixnum(vectorlen(obj_from_$arg))" v))

(define-inline (vector-ref v i)
  (%prim? "obj(vectorref(obj_from_$arg, fixnum_from_$arg))" v i))

(define-inline (vector-set! v i x)
  (%prim! "void(vectorref(obj_from_$arg, fixnum_from_$arg) = obj_from_$arg)" v i x))

(define (subvector-copy! to at from start end)
  (let ([limit (fxmin end (fx+ start (fx- (vector-length to) at)))])
    (if (fx<=? at start)
        (do ([i at (fx+ i 1)] [j start (fx+ j 1)]) 
          [(fx>=? j limit)]
          (vector-set! to i (vector-ref from j)))
        (do ([i (fx+ at (fx- end start 1)) (fx- i 1)] [j (fx- limit 1) (fx- j 1)])
          [(fx<? j start)]
          (vector-set! to i (vector-ref from j))))))

(define (subvector vec start end)
  (let ([v (make-vector (fx- end start))])
    (subvector-copy! v 0 vec start end)
    v))

(define (subvector-fill! vec x start end)
  (do ([i start (fx+ i 1)]) [(fx>=? i end)] (vector-set! vec i x)))


; bytevectors

(%definition "/* bytevectors */")
(%localdef "static cxtype_t cxt_bytevector = { \"bytevector\", free };")
(%localdef "cxtype_t *BYTEVECTOR_NTAG = &cxt_bytevector;")
(%definition "extern cxtype_t *BYTEVECTOR_NTAG;")
(%definition "#define isbytevector(o) (isnative(o, BYTEVECTOR_NTAG))")
(%definition "#define bytevectordata(o) ((int*)getnative(o, BYTEVECTOR_NTAG))")
(%definition "#define bvdatabytes(d) ((unsigned char*)((d)+1))")
(%definition "#define bytevectorlen(o) (*bytevectordata(o))")
(%definition "#define bytevectorbytes(o) (bvdatabytes(bytevectordata(o)))")
(%definition "#define hpushu8v(l, s) hpushptr(s, BYTEVECTOR_NTAG, l)")
(%localdef "#define mallocbvdata(n) cxm_cknull(malloc(sizeof(int)+(n)), \"malloc(bytevector)\")")

(%definition "static int is_byte_obj(obj o) { return (obj_from_fixnum(0) <= o && o <= obj_from_fixnum(255)); } ")
(%definition "#define byte_from_obj(o) byte_from_fixnum(fixnum_from_obj(o))")
(%definition "#ifdef NDEBUG
  #define byte_from_fixnum(n) ((unsigned char)(n))
#else
  static unsigned char byte_from_fixnum(int n) { assert(0 <= n && n <= 255); return n; } 
#endif")
(%definition "#define byte_from_obj(o) byte_from_fixnum(fixnum_from_obj(o))")

(%localdef "unsigned char* bytevectorref(obj o, int i) {
  int *d = bytevectordata(o); assert(i >= 0 && i < *d); return (bvdatabytes(d))+i;
}")
(%definition "#ifdef NDEBUG
  #define bytevectorref(o, i) (bytevectorbytes(o)+(i))
#else
  extern unsigned char* bytevectorref(obj o, int i);
#endif")

(%definition "extern int *newbytevector(unsigned char *s, int n);")
(%localdef "int *newbytevector(unsigned char *s, int n) {
  int *d; assert(s); assert(n >= 0); 
  d = mallocbvdata(n); *d = n; memcpy(bvdatabytes(d), s, n); return d;
}")

(%definition "extern int *makebytevector(int n, int c);")
(%localdef "int *makebytevector(int n, int c) {
  int *d; assert(n >= 0); 
  d = mallocbvdata(n); *d = n; memset(bvdatabytes(d), c, n);
  return d;
}")

(%definition "extern int *allocbytevector(int n);")
(%localdef "int *allocbytevector(int n) {
  int *d = mallocbvdata(n); *d = n; return d;
}")

(%definition "extern int *dupbytevector(int *d);")
(%localdef "int *dupbytevector(int *d0) {
  int *d1 = mallocbvdata(*d0); *d1 = *d0; 
  memcpy(bvdatabytes(d1), bvdatabytes(d0), *d0); 
  return d1;
}")

(%definition "extern int bytevectoreq(int *d0, int *d1);")
(%localdef "int bytevectoreq(int *d0, int *d1) {
  int l0 = *d0, l1 = *d1;
  return (l0 != l1) ? 0 : memcmp(bvdatabytes(d0), bvdatabytes(d1), l0) == 0; 
}")

(%definition "extern int *subbytevector(int *d, int from, int to);")
(%localdef "int *subbytevector(int *d0, int from, int to) {
  int n = to-from, *d1; unsigned char *s0, *s1; assert(d0);
  assert(0 <= from && from <= to && to <= *d0); 
  d1 = mallocbvdata(n); *d1 = n; s0 = bvdatabytes(d0); s1 = bvdatabytes(d1); 
  memcpy(s1, s0+from, n); return d1;
}")

#read #u8<list> as (%const bytevector <list>)

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (bytevector)
      [(_ bytevector (x ...)) (bytevector x ...)] 
      [(_ arg ...) (old-%const arg ...)])))  

(define-inline (byte? x)
  (%prim "bool(is_byte_obj(obj_from_$arg))" x))

(define-inline (bytevector? x)
  (%prim "bool(isbytevector(obj_from_$arg))" x))

(define-syntax make-bytevector
  (syntax-rules ()
    [(_ k) (%prim* "obj(hpushu8v($live, allocbytevector(fixnum_from_$arg)))" k)]
    [(_ k c) (%prim* "obj(hpushu8v($live, makebytevector(fixnum_from_$arg, byte_from_fixnum(fixnum_from_$arg))))" k c)]
    [_ %residual-make-bytevector]))

(define-syntax bytevector
  (syntax-rules ()
    [(_ b ...)
     (%prim* "{ /* bytevector */
    obj o = hpushu8v($live, allocbytevector($argc));
    unsigned char *s = bytevectorbytes(o);
    ${*s++ = byte_from_fixnum(fixnum_from_$arg);
    $}$return obj(o); }" b ...)]
    [_ %residual-bytevector]))

(define-inline (bytevector-length bv)
  (%prim "fixnum(bytevectorlen(obj_from_$arg))" bv))

(define-inline (bytevector-u8-ref bv k)
  (%prim? "fixnum(*bytevectorref(obj_from_$arg, fixnum_from_$arg))" bv k))

(define-inline (bytevector-u8-set! bv k b)
  (%prim! "void(*bytevectorref(obj_from_$arg, fixnum_from_$arg) = byte_from_fixnum(fixnum_from_$arg))" bv k b))

(define-inline (bytevector=? x y)
  (%prim? "bool(bytevectoreq(bytevectordata(obj_from_$arg), bytevectordata(obj_from_$arg)))" x y))

(define (subbytevector-copy! to at from start end)
  (let ([limit (fxmin end (fx+ start (fx- (bytevector-length to) at)))])
    (if (fx<=? at start)
        (do ([i at (fx+ i 1)] [j start (fx+ j 1)]) 
          [(fx>=? j limit)]
          (bytevector-u8-set! to i (bytevector-u8-ref from j)))
        (do ([i (fx+ at (fx- end start 1)) (fx- i 1)] [j (fx- limit 1) (fx- j 1)])
          [(fx<? j start)]
          (bytevector-u8-set! to i (bytevector-u8-ref from j))))))

(define-inline (subbytevector bv start end)
  (%prim*? "{ /* subbytevector */
    int *d = subbytevector(bytevectordata(obj_from_$arg), fixnum_from_$arg, fixnum_from_$arg);
    $return obj(hpushu8v($live, d)); }" bv start end))


; boxes

(%definition "/* boxes */")
(%definition "#define BOX_BTAG 2")  
(%definition "#define isbox(o) istagged(o, BOX_BTAG)")  
(%definition "#define boxref(o) *taggedref(o, BOX_BTAG, 0)")  

(define-inline (box? o)
  (%prim "bool(isbox(obj_from_$arg))" o))

(define-inline (box o) 
  (%prim* "{ /* box */ 
    hreserve(hbsz(2), $live); /* $live live regs */
    *--hp = obj_from_$arg;
    *--hp = obj_from_size(BOX_BTAG); 
    $return obj(hendblk(2)); }" o))

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (box)
      [(_ box x) (box x)] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (unbox b)
  (%prim? "obj(boxref(obj_from_$arg))" b))

(define-inline (set-box! b o)
  (%prim! "void(boxref(obj_from_$arg) = obj_from_$arg)" b o))



; null

; () is immediate with payload 0 and immediate tag 3 (singular null object)

(%definition "/* null */")
(%definition "#define NULL_ITAG 3")  
(%definition "#define mknull() mkimm(0, NULL_ITAG)")  
(%definition "#define isnull(o) ((o) == mkimm(0, NULL_ITAG))")  

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (null)
      [(_ null) (%prim "obj(mknull())")] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (null? x)
  (%prim "bool(isnull(obj_from_$arg))" x))



; pairs and lists

(%definition "/* pairs and lists */")
(%definition "#define PAIR_BTAG 3")  
(%definition "#define ispair(o) istagged(o, PAIR_BTAG)")  
(%definition "#define car(o) *taggedref(o, PAIR_BTAG, 0)")  
(%definition "#define cdr(o) *taggedref(o, PAIR_BTAG, 1)")  

(define-inline (pair? o)
  (%prim "bool(ispair(obj_from_$arg))" o))

(define-inline (atom? o)
  (%prim "bool(!ispair(obj_from_$arg))" o))

(%definition "extern int islist(obj l);")
(%localdef "int islist(obj l) {
  obj s = l;
  for (;;) {
    if (isnull(l)) return 1;
    else if (!ispair(l)) return 0;
    else if ((l = cdr(l)) == s) return 0;
    else if (isnull(l)) return 1;
    else if (!ispair(l)) return 0;
    else if ((l = cdr(l)) == s) return 0;
    else s = cdr(s); 
  }
}")

(define-inline (list? o)
  (%prim? "bool(islist(obj_from_$arg))" o))

(define-inline (cons a d) 
  (%prim* "{ /* cons */ 
    hreserve(hbsz(3), $live); /* $live live regs */
    *--hp = obj_from_$arg;
    *--hp = obj_from_$arg;
    *--hp = obj_from_size(PAIR_BTAG); 
    $return obj(hendblk(3)); }" d a))

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (pair list)
      [(_ pair x y) (cons x y)] 
      [(_ list x ...) (list x ...)] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (car p)
  (%prim? "obj(car(obj_from_$arg))" p))

(define-inline (set-car! p a)
  (%prim! "void(car(obj_from_$arg) = obj_from_$arg)" p a))

(define-inline (cdr p)
  (%prim? "obj(cdr(obj_from_$arg))" p))

(define-inline (set-cdr! p d)
  (%prim! "void(cdr(obj_from_$arg) = obj_from_$arg)" p d))

(define-syntax c?r
  (syntax-rules (a d)
    [(c?r x) x]
    [(c?r a ? ... x) (car (c?r ? ... x))]
    [(c?r d ? ... x) (cdr (c?r ? ... x))]))

(define-inline (caar x) (c?r a a x))
(define-inline (cadr x) (c?r a d x))
(define-inline (cdar x) (c?r d a x))
(define-inline (cddr x) (c?r d d x))
(define-inline (caaar x) (c?r a a a x))
(define-inline (caadr x) (c?r a a d x))
(define-inline (cadar x) (c?r a d a x))
(define-inline (caddr x) (c?r a d d x))
(define-inline (cdaar x) (c?r d a a x))
(define-inline (cdadr x) (c?r d a d x))
(define-inline (cddar x) (c?r d d a x))
(define-inline (cdddr x) (c?r d d d x))
(define-inline (caaaar x) (c?r a a a a x))
(define-inline (caaadr x) (c?r a a a d x))
(define-inline (caadar x) (c?r a a d a x))
(define-inline (caaddr x) (c?r a a d d x))
(define-inline (cadaar x) (c?r a d a a x))
(define-inline (cadadr x) (c?r a d a d x))
(define-inline (caddar x) (c?r a d d a x))
(define-inline (cadddr x) (c?r a d d d x))
(define-inline (cdaaar x) (c?r d a a a x))
(define-inline (cdaadr x) (c?r d a a d x))
(define-inline (cdadar x) (c?r d a d a x))
(define-inline (cdaddr x) (c?r d a d d x))
(define-inline (cddaar x) (c?r d d a a x))
(define-inline (cddadr x) (c?r d d a d x))
(define-inline (cdddar x) (c?r d d d a x))
(define-inline (cddddr x) (c?r d d d d x))

(define (%make-list n i)
  (let loop ([n n] [l '()])
    (if (<= n 0) l (loop (- n 1) (cons i l))))) 

(define-syntax make-list
  (syntax-rules ()
    [(_ n) (%make-list n (void))]
    [(_ n i) (%make-list n i)]
    [_ %residual-make-list]))

(define-syntax list
  (syntax-rules ()
    [(_) '()]
    [(_ x . more) (cons x (list . more))]
    [_ %residual-list]))

(define-syntax cons*
  (syntax-rules ()
    [(_ i ... j)
     (%prim*/rev "{ /* cons* */
    obj p;
    hreserve(hbsz(3)*$argc, $live); /* $live live regs */
    p = obj_from_$arg; /* gc-safe */
    ${*--hp = p; *--hp = obj_from_$arg;
    *--hp = obj_from_size(PAIR_BTAG); p = hendblk(3);
    $}$return obj(p); }" i ... j)]
    [_ %residual-cons*]))

(define-syntax list* cons*)

(define-inline (length l)
  (%prim? "{ /* length */
    int n; obj l = obj_from_$arg;
    for (n = 0; l != mknull(); ++n, l = cdr(l)) ;
    $return fixnum(n); }" l)) 

(define-inline (reverse l)
  (%prim*? "{ /* reverse */
    obj l, o = mknull(); int c = fixnum_from_$arg;
    hreserve(hbsz(3)*c, $live); /* $live live regs */
    l = obj_from_$arg; /* gc-safe */
    for (; l != mknull(); l = cdr(l)) { *--hp = o; *--hp = car(l);
    *--hp = obj_from_size(PAIR_BTAG); o = hendblk(3); }  
    $return obj(o); }" (length l) l))

(define-inline (reverse! l)
  (%prim?! "{ /* reverse! */
    obj t, v = mknull(), l = obj_from_$arg;
    while (l != mknull()) t = cdr(l), cdr(l) = v, v = l, l = t;
    $return obj(v); }" l))

(define (%append l o)
  (%prim*? "{ /* append */
    obj t, l, o, *p, *d; int c = fixnum_from_$arg;
    hreserve(hbsz(3)*c, $live); /* $live live regs */
    l = obj_from_$arg; t = obj_from_$arg; /* gc-safe */
    o = t; p = &o; 
    for (; l != mknull(); l = cdr(l)) {
    *--hp = t; d = hp; *--hp = car(l);
    *--hp = obj_from_size(PAIR_BTAG); 
    *p = hendblk(3); p = d; }  
    $return obj(o); }" (length l) l o))

(define-syntax append
  (syntax-rules ()
    [(_) '()] [(_ x) x]
    [(_ x y) (%append x y)]
    [(_ x y z ...) (%append x (append y z ...))]
    [_ %residual-append]))

(define (list-copy obj)
  (if (pair? obj)
      (cons (car obj) (list-copy (cdr obj)))
      obj))

(define-inline (list-ref l n)
  (%prim? "{ /* list-ref */
    obj l = obj_from_$arg; int c = fixnum_from_$arg;
    while (c-- > 0) l = cdr(l);
    $return obj(car(l)); }" l n)) 

(define-inline (list-tail l n)
  (%prim? "{ /* list-tail */
    obj l = obj_from_$arg; int c = fixnum_from_$arg;
    while (c-- > 0) l = cdr(l);
    $return obj(l); }" l n)) 

(define-inline (list-set! l n obj)
  (set-car! (list-tail list n) obj)) 

(define-inline (last-pair l)
  (%prim? "{ /* last-pair */
    obj l = obj_from_$arg, p;
    for (p = cdr(l); ispair(p); p = cdr(p)) l = p;
    $return obj(l); }" l)) 

(define-syntax map
  (syntax-rules ()
    [(_ fun lst)
     (let ([f fun]) 
       (let loop ([l lst]) 
         (if (pair? l) (cons (f (car l)) (loop (cdr l))) '())))]
    [(_ fun lst . l*) (%residual-map fun lst . l*)]
    [_ %residual-map])) 

(define-syntax for-each
  (syntax-rules ()
    [(_ fun lst)
     (let ([f fun]) 
       (let loop ([l lst]) 
         (if (pair? l) (begin (f (car l)) (loop (cdr l))))))]
    [(_ fun lst . l*) (%residual-for-each fun lst . l*)]
    [_ %residual-for-each]))



; symbols

; symbols are 24-bit immediates with immediate tag 4

(%definition "/* symbols */")
(%definition "#define SYMBOL_ITAG 4")  
(%definition "#define issymbol(o) (isimm(o, SYMBOL_ITAG))")
(%definition "#define mksymbol(i) mkimm(i, SYMBOL_ITAG)")
(%definition "#define getsymbol(o) getimmu(o, SYMBOL_ITAG)")

(%localdef "static struct { char **a; char ***v; size_t sz; size_t u; size_t maxu; } symt;")
(%localdef "static unsigned long hashs(char *s) {
  unsigned long i = 0, l = (unsigned long)strlen(s), h = l;
  while (i < l) h = (h << 4) ^ (h >> 28) ^ s[i++];
  return h ^ (h  >> 10) ^ (h >> 20);
}")

(%definition "extern char *symbolname(int sym);")
(%localdef "char *symbolname(int sym) {
  assert(sym >= 0); assert(sym < (int)symt.u);
  return symt.a[sym];
}")

(%definition "extern int internsym(char *name);")
(%localdef "int internsym(char *name) {
  size_t i, j; /* based on a code (C) 1998, 1999 by James Clark. */
  if (symt.sz == 0) { /* init */
    symt.a = cxm_cknull(calloc(64, sizeof(char*)), \"symtab[0]\");
    symt.v = cxm_cknull(calloc(64, sizeof(char**)), \"symtab[1]\");
    symt.sz = 64, symt.maxu = 64 / 2;
    i = hashs(name) & (symt.sz-1);
  } else {
    unsigned long h = hashs(name);
    for (i = h & (symt.sz-1); symt.v[i]; i = (i-1) & (symt.sz-1))
      if (strcmp(name, *symt.v[i]) == 0) return (int)(symt.v[i] - symt.a);
    if (symt.u == symt.maxu) { /* rehash */
      size_t nsz = symt.sz * 2;
      char **na = cxm_cknull(calloc(nsz, sizeof(char*)), \"symtab[2]\");
      char ***nv = cxm_cknull(calloc(nsz, sizeof(char**)), \"symtab[3]\");
      for (i = 0; i < symt.sz; i++)
        if (symt.v[i]) {
          for (j = hashs(*symt.v[i]) & (nsz-1); nv[j]; j = (j-1) & (nsz-1)) ;
          nv[j] = symt.v[i] - symt.a + na;
        }
      free(symt.v); symt.v = nv; symt.sz = nsz; symt.maxu = nsz / 2;
      memcpy(na, symt.a, symt.u * sizeof(char*)); free(symt.a); symt.a = na; 
      for (i = h & (symt.sz-1); symt.v[i]; i = (i-1) & (symt.sz-1)) ;
    }
  }
  *(symt.v[i] = symt.a + symt.u) = 
    strcpy(cxm_cknull(malloc(strlen(name)+1), \"symtab[4]\"), name);
  return (int)((symt.u)++);
}")

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (symbol)
      ; wrap code in #() to force constant lifting
      [(_ symbol s)
       (%prim #("obj(mksymbol(internsym(\"" s "\")))"))]
      [(_ symbol 8 c ...)
       (%prim #("{ static obj o = 0; static char s[] = { " (c ", ") ... "0 };\n"
               "    $return obj(o ? o : (o = mksymbol(internsym(s)))); }"))]
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (symbol? x)
  (%prim "bool(issymbol(obj_from_$arg))" x))

(define-syntax symbol=?
  (syntax-rules ()
    [(_ x y) (%prim "bool(getsymbol(obj_from_$arg) == getsymbol(obj_from_$arg))" x y)]
    [(_ x y z ...) (let ([t y]) (and (symbol=? x t) (symbol=? t z ...)))]
    [_ %residual-symbol=?]))



; records

; records are typed blocks with rtd (non-immediate object) as type

(%definition "/* records */")
(%definition "#define isrecord(o) istyped(o)")  
(%definition "#define recordrtd(r) *typedtype(r)")  
(%definition "#define recordlen(r) typedlen(r)")  
(%definition "#define recordref(r, i) *typedref(r, i)")  

(define-syntax record?
  (syntax-rules ()
    [(_ o) (%prim "bool(isrecord(obj_from_$arg))" o)]
    [(_ o t) (%prim "{ /* record? */
    obj o = obj_from_$arg, t = obj_from_$arg; 
    if (!isrecord(o)) $return bool(0);
    else $return bool(recordrtd(o) == t); }" o t)]
    [_ %residual-record?]))

(define-inline (make-record rtd n)
  (%prim* "{ /* make-record */
    int c = fixnum_from_$arg;
    hreserve(hbsz(c+1), $live); /* $live live regs */
    hp -= c; memset(hp, 0, c * sizeof(obj));
    *--hp = obj_from_$arg; assert(isobjptr(*hp));
    $return obj(hendblk(c+1)); }" n rtd))

(define-inline (record-type-descriptor r)
  (%prim "obj(recordrtd(obj_from_$arg))" r))

(define-inline (record-length r)
  (%prim "fixnum(recordlen(obj_from_$arg))" r))

(define-inline (record-ref r i)
  (%prim? "obj(recordref(obj_from_$arg, fixnum_from_$arg))" r i))

(define-inline (record-set! r i x)
  (%prim! "void(recordref(obj_from_$arg, fixnum_from_$arg) = obj_from_$arg)" r i x))

(define-inline (new-record-type name fields) ; stub
  (cons name fields))

; works on top and locally, but field names cannot be hygienically generated on top level
(define-syntax define-record-type
  (letrec-syntax
    ([id-eq?? ; see http://okmij.org/ftp/Scheme/macro-symbol-p.txt
      (syntax-rules ()
        [(_ id b kt kf)
         ((syntax-lambda (id ok) ((syntax-rules () [(_ b) (id)]) ok))
          (syntax-rules () [(_) kf]) (syntax-rules () [(_) kt]))])]
     [id-assq??
      (syntax-rules ()
        [(_ id () kt kf) kf]
        [(_ id ([id0 . r0] . idr*) kt kf) (id-eq?? id id0 (kt . r0) (id-assq?? id idr* kt kf))])]
     [init
      (syntax-rules ()
        [(_  r () fi* (x ...)) (begin x ... r)]
        [(_  r (id0 . id*) fi* (x ...))
         (id-assq?? id0 fi* 
           (syntax-rules () [(_ i0) (init r id* fi* (x ... (record-set! r i0 id0)))]) 
           (syntax-error "id in define-record-type constructor is not a field:" id0))])]
     [unroll
      (syntax-rules ()
        [(_ rtn (consn id ...) predn () ([f i] ...) ([a ia] ...) ([m im] ...))
         (begin
            (define rtn (new-record-type 'rtn '(f ...)))
            (define consn (lambda (id ...) (let ([r (make-record rtn #&(length (f ...)))]) (init r (id ...) ([f i] ...) ()))))
            (define predn (lambda (obj) (record? obj rtn)))
            (define a (lambda (obj) (record-ref obj ia))) ...
            (define m (lambda (obj val) (record-set! obj im val))) ...)]
        [(_ rtn cf* predn ([fn accn] fam ...) (fi ...) (ai ...) (mi ...))
         (unroll rtn cf* predn (fam ...) 
           (fi ... [fn #&(length (fi ...))]) (ai ... [accn #&(length (fi ...))]) (mi ...))]
        [(_  rtn cf* predn ([fn accn modn] fam ...) (fi ...) (ai ...) (mi ...))
         (unroll rtn cf* predn (fam ...) 
           (fi ... [fn #&(length (fi ...))]) (ai ... [accn #&(length (fi ...))]) (mi ... [modn #&(length (fi ...))]))])])
    (syntax-rules ()
      [(_ rtn (consn id ...) predn (fn . am) ...)
       (unroll rtn (consn id ...) predn ((fn . am) ...) () () ())])))



; conversions

(define-inline (symbol->string s)
  (%prim* "obj(hpushstr($live, newstring(symbolname(getsymbol(obj_from_$arg)))))" s))

(define-inline (string->symbol s)
  (%prim? "obj(mksymbol(internsym(stringchars(obj_from_$arg))))" s))

(define (fixnum->string n r)
  (%prim* "{ /* fixnum->string */
    char buf[35], *s = buf + sizeof(buf) - 1; 
    int neg = 0;
    long num = fixnum_from_$arg;
    long radix = fixnum_from_$arg;
    if (num < 0) { neg = 1; num = -num; }
    *s = 0;
    do { int d = num % radix; *--s = d < 10 ? d + '0' : d - 10 + 'a'; }
    while (num /= radix);
    if (neg) *--s = '-';
    $return obj(hpushstr($live, newstring(s))); }" n r))

(define (flonum->string x)
  (%prim* "{ /* flonum->string */
    char buf[30], *s; double d = flonum_from_$arg; sprintf(buf, \"%.15g\", d);
    for (s = buf; *s != 0; s++) if (strchr(\".eE\", *s)) break;
    if (d != d) strcpy(buf, \"+nan.0\"); else if (d <= -HUGE_VAL) strcpy(buf, \"-inf.0\");
    else if (d >= HUGE_VAL) strcpy(buf, \"+inf.0\"); else if (*s == 'E') *s = 'e'; 
    else if (*s == 0) {  *s++ = '.'; *s++ = '0'; *s = 0; }
    $return obj(hpushstr($live, newstring(buf))); }" x))

(define-syntax number->string
  (syntax-rules ()
    [(_ n r) (if (fixnum? n) (fixnum->string n r) (flonum->string n))]
    [(_ n) (if (fixnum? n) (fixnum->string n 10) (flonum->string n))]
    [_ %residual-number->string]))

(define (string->fixnum s r)
  (%prim? "{ /* string->fixnum */
    char *e, *s = stringchars(obj_from_$arg);
    int radix = fixnum_from_$arg; long l;
    if (s[0] == '#' && (s[1] == 'b' || s[1] == 'B')) s += 2, radix = 2;
    else if (s[0] == '#' && (s[1] == 'o' || s[1] == 'O')) s += 2, radix = 8;
    else if (s[0] == '#' && (s[1] == 'd' || s[1] == 'D')) s += 2, radix = 10;
    else if (s[0] == '#' && (s[1] == 'x' || s[1] == 'X')) s += 2, radix = 16;
    l = (errno = 0, strtol(s, &e, radix));
    if (errno || l < FIXNUM_MIN || l > FIXNUM_MAX || e == s || *e) $return bool(0);
    else $return fixnum(l); }" s r))

(define (string->flonum s)
  (%prim*? "{ /* string->flonum */
    char *e = \"\", *s = stringchars(obj_from_$arg); double d; errno = 0;
    if (*s != '+' && *s != '-') d = strtod(s, &e);
    else if (strcmp_ci(s+1, \"inf.0\") == 0) d = (*s == '-' ? -HUGE_VAL : HUGE_VAL); 
    else if (strcmp_ci(s+1, \"nan.0\") == 0) d = HUGE_VAL - HUGE_VAL;
    else d = strtod(s, &e);
    if (errno || e == s || *e) $return bool(0);
    else $return flonum($live, d); }" s))

(define-inline (string->fixnum-or-flonum s r)
  (%prim*? "{ /* string->fixnum-or-flonum */
    char *s = stringchars(obj_from_$arg);
    int radix = fixnum_from_$arg; long l; double d;
    if (0) $return obj(0); /* to fool sfc unboxer */
    switch (strtofxfl(s, radix, &l, &d)) {
    case 'e': $return fixnum(l); break;
    case 'i': $return flonum($live, d); break;
    default : $return bool(0); break;
    } }" s r)) 

(define-syntax string->number
  (syntax-rules ()
    [(_ s r) (string->fixnum-or-flonum s r)]
    [(_ s) (string->fixnum-or-flonum s 10)]
    [_ %residual-string->number]))

(define (subvector->list vec start end)
  (let loop ([i (fx- end 1)] [l '()])
    (if (fx<? i start) l (loop (fx- i 1) (cons (vector-ref vec i) l)))))

(define (list->vector l)
  (%prim*? "{ /* list->vector */
    obj l; int i, c = fixnum_from_$arg;
    hreserve(hbsz(c+1), $live); /* $live live regs */
    l = obj_from_$arg; /* gc-safe */
    for (i = 0; i < c; ++i, l = cdr(l)) hp[i-c] = car(l);
    hp -= c; *--hp = obj_from_size(VECTOR_BTAG);
    $return obj(hendblk(c+1)); }" (length l) l))

(define (list->string l)
  (%prim*? "{ /* list->string */
    int i, c = fixnum_from_$arg; 
    obj o = hpushstr($live, allocstring(c, ' ')); /* $live live regs */
    obj l = obj_from_$arg; /* gc-safe */
    unsigned char *s = (unsigned char *)stringchars(o);
    for (i = 0; i < c; ++i, l = cdr(l)) s[i] = (unsigned char)char_from_obj(car(l));
    $return obj(o); }" (length l) l))

(define (substring->list str start end)
  (let loop ([i (fx- end 1)] [l '()])
    (if (fx<? i start) l (loop (fx- i 1) (cons (string-ref str i) l)))))

(define (%subvector-string-copy! to at from start end)
  (let ([limit (fxmin end (fx+ start (fx- (string-length to) at)))])
    (do ([i at (fx+ i 1)] [j start (fx+ j 1)]) 
      [(fx>=? j limit) to]
      (string-set! to i (vector-ref from j)))))

(define (subvector->string vec start end)
  (%subvector-string-copy! (make-string (fx- end start)) 0 vec start end))

(define (%substring-vector-copy! to at from start end)
  (let ([limit (fxmin end (fx+ start (fx- (vector-length to) at)))])
    (do ([i at (fx+ i 1)] [j start (fx+ j 1)]) 
      [(fx>=? j limit) to]
      (vector-set! to i (string-ref from j)))))

(define (substring->vector str start end)
  (%substring-vector-copy! (make-vector (fx- end start)) 0 str start end))

(define (list->bytevector l)
  (%prim*? "{ /* list->bytevector */
    int i, c = fixnum_from_$arg; 
    obj o = hpushu8v($live, allocbytevector(c)); /* $live live regs */
    obj l = obj_from_$arg; /* gc-safe */
    unsigned char *s = bytevectorbytes(o);
    for (i = 0; i < c; ++i, l = cdr(l)) s[i] = byte_from_obj(car(l));
    $return obj(o); }" (length l) l))

(define (subbytevector->list vec start end)
  (let loop ([i (fx- end 1)] [l '()])
    (if (fx<? i start) l (loop (fx- i 1) (cons (bytevector-u8-ref vec i) l)))))



; control

; closure procedures are heap blocks of length >= 1 which
; have a pointer to the static code entry as 0th element;
; sfc allocates env-less global procedures in static memory,
; so procedure? answers #t to any nonzero out-of-heap pointer

(%localdef "int isprocedure(obj o) {
  if (!o) return 0;
  else if (isaptr(o) && !isobjptr(o)) return 1;
  else if (!isobjptr(o)) return 0;
  else { obj h = objptr_from_obj(o)[-1];
    return notaptr(h) && size_from_obj(h) >= 1 
      && isaptr(hblkref(o, 0)); }
}")

(%localdef "int procedurelen(obj o) {
  assert(isprocedure(o));
  return isobjptr(o) ? hblklen(o) : 1;
}")

(%localdef "obj* procedureref(obj o, int i) {
  int len; assert(isprocedure(o));
  len = isobjptr(o) ? hblklen(o) : 1;
  assert(i >= 0 && i < len);
  return &hblkref(o, i);   
}")

(%definition "/* procedures */")
(%definition "extern int isprocedure(obj o);")
(%definition "extern int procedurelen(obj o);")
(%definition "extern obj* procedureref(obj o, int i);")

(define-inline (procedure? o)
  (%prim "bool(isprocedure(obj_from_$arg))" o))


; apply, dotted lambda list, argc dispatch, case-lambda

(%definition "/* apply and dotted lambda list */")
(%definition "extern obj appcases[];")
(%localdef "/* apply/dotted lambda adapter entry points */")
(%localdef "static obj apphost(obj);")
(%localdef "obj appcases[5] = { (obj)apphost,  (obj)apphost,  (obj)apphost,  (obj)apphost ,  (obj)apphost };")
(%localdef "/* apphost procedure */
#define APPLY_MAX_REGS 1024 /* limit on rc for apply & friends */
static obj apphost(obj pc)
{
  register obj *r = cxg_regs;
  register obj *hp = cxg_hp;
  register int rc = cxg_rc;
jump: 
  switch (objptr_from_obj(pc)-appcases) {

case 0: /* apply */
    /* clo k f arg... arglist */
    assert(rc >= 4);
    { int i; obj l;
    rreserve(APPLY_MAX_REGS);
    l = r[--rc];
    r[0] = r[2];
    /* k in r[1] */
    for (i = 3; i < rc; ++i) r[i-1] = r[i];
    for (--rc; l != mknull(); l = cdr(l)) r[rc++] = car(l);
    /* f k arg... arg... */
    assert(rc <= APPLY_MAX_REGS);
    pc = objptr_from_obj(r[0])[0];
    goto jump; }

case 1: /* dotted lambda adapter */
    /* clo k arg... */
    { obj* p = objptr_from_obj(r[0]);
    int n = fixnum_from_obj(p[1]) + 2; 
    r[0] = p[2]; /* f */
    /* k in r[1] */
    assert(rc >= n);
    rreserve(n+1);
    if (rc == n) r[rc++] = mknull();
    else { /* collect rest list */
    obj l = mknull();
    hreserve(hbsz(3)*(rc-n), rc);
    while (rc > n) { *--hp = l; *--hp = r[--rc];
    *--hp = obj_from_size(PAIR_BTAG); l = hendblk(3); }
    r[rc++] = l; }
    /* f k arg... arglist */
    pc = objptr_from_obj(r[0])[0];
    goto jump; }

case 2: /* void continuation adapter */
    /* cclo ek arg ... */
    assert(rc >= 2);
    { obj* p = objptr_from_obj(r[0]);
    r[0] = p[1]; /* cont */
    pc = objptr_from_obj(r[0])[0];
    /* ek in r[1] */
    rreserve(3);
    r[2] = obj_from_void(0);
    rc = 3;
    goto jump; }

case 3: /* argc dispatcher */
    /* clo k arg... */
    { obj* p = objptr_from_obj(r[0]);
    obj pv = p[1]; int vl = vectorlen(pv); assert(vl > 0);
    if (rc-2 < vl-1) r[0] = vectorref(pv, rc-2); /* matching slot */
    else r[0] = vectorref(pv, vl-1); /* catch-all slot */
    pc = objptr_from_obj(r[0])[0];
    goto jump; }

case 4: /* case lambda dispatcher */
    /* clo k arg... */
    { obj* p = objptr_from_obj(r[0]); int bl = hblklen(p), i;
    for (i = 1; i < bl; i += 3) {
    int min = fixnum_from_obj(hblkref(p, i)), max = fixnum_from_obj(hblkref(p, i+1));
    if (min <= rc-2 && rc-2 <= max) { r[0] = hblkref(p, i+2); break; }
    } assert(i < bl); /* at least one of the cases should match! */ 
    pc = objptr_from_obj(r[0])[0];
    goto jump; }

default: /* inter-host call */
    cxg_hp = hp;
    cxm_rgc(r, 1);
    cxg_rc = rc;
    return pc;
  }
}")

(define apply 
  (%prim "{ /* define apply */
    static obj c[] = { obj_from_objptr(appcases+0) }; 
    $return objptr(c); }"))

(define-inline (make-improper-lambda n lam)
  (%prim* "{ /* make-improper-lambda */
    hreserve(hbsz(3), $live); /* $live live regs */
    *--hp = obj_from_$arg;
    *--hp = obj_from_$arg;
    *--hp = obj_from_objptr(appcases+1);
    $return obj(hendblk(3)); }" lam n))

(define-inline (make-void-continuation k)
  (%prim* "{ /* make-void-continuation */
    hreserve(hbsz(2), $live); /* $live live regs */
    *--hp = obj_from_$arg;
    *--hp = obj_from_objptr(appcases+2);
    $return obj(hendblk(2)); }" k))

(define-inline (make-argc-dispatch-lambda pv)
  (%prim* "{ /* make-argc-dispatch-lambda */
    hreserve(hbsz(2), $live); /* $live live regs */
    *--hp = obj_from_$arg;
    *--hp = obj_from_objptr(appcases+3);
    $return obj(hendblk(2)); }" pv))

(define-syntax argc-dispatch-lambda
  (syntax-rules ()
    [(_ x ...) (make-argc-dispatch-lambda (vector x ...))]))

(define-inline (argc-dispatch-lambda? x)
  (%prim "{ /* argc-dispatch-lambda? */
    obj x = obj_from_$arg;
    $return bool(isprocedure(x) && *procedureref(x, 0) == obj_from_objptr(appcases+3)); }" x))

(define-syntax make-case-lambda 
  (syntax-rules ()
    [(_ x ...) ; order is: min1 max1 lambda1 min2 max2 lambda2 ...
     (%prim*/rev "{ /* make-case-lambda */
    hreserve(hbsz($argc+1), $live); /* $live live regs */
    ${*--hp = obj_from_$arg;
    $}*--hp = obj_from_objptr(appcases+4);
    $return obj(hendblk($argc+1)); }" x ...)]
    [_ %residual-make-case-lambda]))

(define-syntax case-lambda
  (letrec-syntax
    ([min-accepted
      (syntax-rules ()
        [(_ () N) N] [(_ (a . d) N) (min-accepted d #&(+ 1 N))] [(_ ra N) N])]
     [max-accepted
      (syntax-rules ()
        [(_ () N) N] [(_ (a . d) N) (max-accepted d #&(+ 1 N))] [(_ ra N) (%prim "fixnum(FIXNUM_MAX)")])]
     [unroll-cases
      (syntax-rules ()
        [(_ () c ...) 
         (make-case-lambda c ... 0 (%prim "fixnum(FIXNUM_MAX)") %fail-lambda)]
        [(_ ([formals . body] . more) c ...)
         (unroll-cases more c ... 
           (min-accepted formals 0) (max-accepted formals 0) (lambda formals . body))])])
     (syntax-rules ()
       [(_ [formals . body] ...)
        (unroll-cases ([formals . body] ...))])))


; parameters, r7rs-style

(define make-parameter
  (case-lambda
    [(value) 
     (case-lambda 
       [() value]
       [(x) (set! value x)]
       [(x s) (if s (set! value x) x)])]
    [(init converter)
     (let ([value (converter init)])
       (case-lambda 
         [() value]
         [(x) (set! value (converter x))]
         [(x s) (if s (set! value x) (converter x))]))]))

(define-syntax parameterize
  (letrec-syntax
    ([loop 
      (syntax-rules ()
        [(_ ([param value p old new] ...) () body)
         (let ([p param] ...)
           (let ([old (p)] ... [new (p value #f)] ...)
             (dynamic-wind
               (lambda () (p new #t) ...)
               (lambda () . body)
               (lambda () (p old #t) ...))))]
        [(_ args ([param value] . rest) body)
         (loop ([param value p old new] . args) rest body)])])
    (syntax-rules ()
      [(_ ([param value] ...) . body)
       (loop () ([param value] ...) body)])))


; delay & force, r7rs-style

(define promise? box?)

(define (make-promise o) (box (cons #t o)))
(define (make-lazy-promise o) (box (cons #f o)))

(define (force p)
  (let ([pc (unbox p)])
    (if (car pc)
        (cdr pc)
        (let* ([newp ((cdr pc))] [pc (unbox p)])
          (unless (car pc)
            (set-car! pc (car (unbox newp)))
            (set-cdr! pc (cdr (unbox newp)))
            (set-box! newp pc))
          (force p)))))

(define-syntax delay-force
  (syntax-rules () [(_ x) (make-lazy-promise (lambda () x))]))

(define-syntax delay
  (syntax-rules () [(_ x) (delay-force (make-promise x))]))



; eof

; eof is tagged immediate with payload 0 and immediate tag 7 

(%definition "/* eof */")
(%definition "#define EOF_ITAG 7")  
(%definition "#define mkeof() mkimm(0, EOF_ITAG)")  
(%definition "#define iseof(o) ((o) == mkimm(0, EOF_ITAG))")  

(define-syntax %const
  (let-syntax ([old-%const %const])
    (syntax-rules (eof)
      [(_ eof) (%prim "obj(mkeof())")] 
      [(_ arg ...) (old-%const arg ...)]))) 

(define-inline (eof-object)
  (%prim "obj(mkeof())"))

(define-inline (eof-object? x)
  (%prim "bool(iseof(obj_from_$arg))" x))


; i/o ports

; internal helper fo opening regular files
(define-inline (open-file* fn mode) ;=> #f (i.e. NULL) or foreign ptr
  (%prim*?! "obj((obj)fopen(stringchars(obj_from_$arg), stringchars(obj_from_$arg)))" fn mode))

; generic input ports

(%definition "/* input ports */")
(%definition "typedef struct { /* extends cxtype_t */
  const char *tname;
  void (*free)(void*);
  int (*close)(void*);
  int (*getch)(void*);
  int (*ungetch)(int, void*);
} cxtype_iport_t;")

(%definition "extern cxtype_t *IPORT_CLOSED_NTAG;")
(%definition "extern cxtype_t *IPORT_FILE_NTAG;")
(%definition "extern cxtype_t *IPORT_STRING_NTAG;")
(%definition "extern cxtype_t *IPORT_BYTEVECTOR_NTAG;")
(%definition "static cxtype_iport_t *iportvt(obj o) { 
  cxtype_t *pt; if (!isobjptr(o)) return NULL;
  pt = (cxtype_t*)objptr_from_obj(o)[-1];
  if (pt != IPORT_CLOSED_NTAG && pt != IPORT_FILE_NTAG &&
      pt != IPORT_STRING_NTAG && pt != IPORT_BYTEVECTOR_NTAG) return NULL; 
  else return (cxtype_iport_t*)pt; }")
(%definition "#define ckiportvt(o) ((cxtype_iport_t*)cxm_cknull(iportvt(o), \"iportvt\"))")  
(%definition "#define isiport(o) (iportvt(o) != NULL)")
(%definition "#define iportdata(o) ((void*)(*objptr_from_obj(o)))")

(%definition "static int iportgetc(obj o) {
  cxtype_iport_t *vt = iportvt(o); void *pp = iportdata(o);
  assert(vt); return vt->getch(pp);
}")
(%definition "static int iportpeekc(obj o) {
  cxtype_iport_t *vt = iportvt(o); void *pp = iportdata(o); int c;
  assert(vt); c = vt->getch(pp); if (c != EOF) vt->ungetch(c, pp); return c;
}")

(define-inline (input-port? x)
  (%prim "bool(isiport(obj_from_$arg))" x))

(define-inline (port-fold-case? ip) ;stub
  (%prim? "bool(((void)ckiportvt(obj_from_$arg), 0))" ip))

(define-inline (set-port-fold-case! ip b) ;stub
  (%prim?! "void(ckiportvt(obj_from_$arg))" ip))


; closed input ports 

(%definition "/* closed input ports */")
(%localdef "static void cifree(void *p) {}")
(%localdef "static int ciclose(void *p) { return 0; }")
(%localdef "static int cigetch(void *p) { return EOF; }")
(%localdef "static int ciungetch(int c) { return c; }")
(%localdef "static cxtype_iport_t cxt_iport_closed = {
  \"closed-input-port\", (void (*)(void*))cifree, (int (*)(void*))ciclose,
  (int (*)(void*))cigetch, (int (*)(int, void*))ciungetch };")
(%localdef "cxtype_t *IPORT_CLOSED_NTAG = (cxtype_t *)&cxt_iport_closed;")

(define (close-input-port p)
  (%prim?! "{ /* close-input-port */
    obj o = obj_from_$arg; cxtype_iport_t *vt = iportvt(o); assert(vt);
    vt->close(iportdata(o)); vt->free(iportdata(o));  
    objptr_from_obj(o)[-1] = (obj)IPORT_CLOSED_NTAG; 
    $return void(0); }" p)) 

(define-inline (input-port-open? p)
  (%prim? "bool(ckiportvt(obj_from_$arg) != (cxtype_iport_t *)IPORT_CLOSED_NTAG)" p))

; file input ports

(%localdef "static void ffree(void *vp) {
  /* FILE *fp = vp; assert(fp); cannot fclose(fp) here because of FILE reuse! */ }")
(%localdef "static cxtype_iport_t cxt_iport_file = {
  \"file-input-port\", ffree, (int (*)(void*))fclose,
  (int (*)(void*))(fgetc), (int (*)(int, void*))(ungetc) };")
(%localdef "cxtype_t *IPORT_FILE_NTAG = (cxtype_t *)&cxt_iport_file;")
(%definition "#define mkiport_file(l, fp) hpushptr(fp, IPORT_FILE_NTAG, l)")

(define *current-input-port* (%prim* "obj(mkiport_file($live, stdin))"))

(define-syntax current-input-port ; parameter
  (syntax-rules ()
    [(_) *current-input-port*]
    [(_ p) (set! *current-input-port* p)]
    [(_ p s) (if s (set! *current-input-port* p) p)]
    [_ %residual-current-input-port]))

(define-inline (open-input-file fn)
  (let ([file* (open-file* fn "r")])
    (if file* (%prim*?! "obj(mkiport_file($live, (void*)(obj_from_$arg)))" file*)
        (file-error "cannot open input file" fn))))

(define-inline (open-binary-input-file fn)
  (let ([file* (open-file* fn "rb")])
    (if file* (%prim*?! "obj(mkiport_file($live, (void*)(obj_from_$arg)))" file*)
        (file-error "cannot open binary input file" fn))))

; string input ports 

(%definition "/* string input ports */")
(%definition "typedef struct { char *p; void *base; } sifile_t;")
(%localdef "sifile_t *sialloc(char *p, void *base) { 
  sifile_t *fp = cxm_cknull(malloc(sizeof(sifile_t)), \"malloc(sifile)\");
  fp->p = p; fp->base = base; return fp; }")
(%definition "extern sifile_t *sialloc(char *p, void *base);")
(%localdef "static void sifree(sifile_t *fp) { 
  assert(fp); if (fp->base) free(fp->base); free(fp); }")
(%localdef "static int siclose(sifile_t *fp) { 
  assert(fp); if (fp->base) free(fp->base); fp->base = NULL; fp->p = \"\"; return 0; }")
(%localdef "static int sigetch(sifile_t *fp) {
  int c; assert(fp && fp->p); if (!(c = *(fp->p))) return EOF; ++(fp->p); return c; }")
(%localdef "static int siungetch(int c, sifile_t *fp) {
  assert(fp && fp->p); --(fp->p); assert(c == *(fp->p)); return c; }")
(%localdef "static cxtype_iport_t cxt_iport_string = {
  \"string-input-port\", (void (*)(void*))sifree, (int (*)(void*))siclose,
  (int (*)(void*))sigetch, (int (*)(int, void*))siungetch };")
(%localdef "cxtype_t *IPORT_STRING_NTAG = (cxtype_t *)&cxt_iport_string;")
(%definition "#define mkiport_string(l, fp) hpushptr(fp, IPORT_STRING_NTAG, l)")

(define-inline (open-input-string s)
  (%prim*? "{ /* open-input-string */
    int *d = dupstring(stringdata(obj_from_$arg));
    $return obj(mkiport_string($live, sialloc(sdatachars(d), d))); }" s))

; bytevector input ports 

(%definition "/* bytevector input ports */")
(%definition "typedef struct { unsigned char *p, *e; void *base; } bvifile_t;")
(%localdef "bvifile_t *bvialloc(unsigned char *p, unsigned char *e, void *base) { 
  bvifile_t *fp = cxm_cknull(malloc(sizeof(bvifile_t)), \"malloc(bvifile)\");
  fp->p = p; fp->e = e; fp->base = base; return fp; }")
(%definition "extern bvifile_t *bvialloc(unsigned char *p, unsigned char *e, void *base);")
(%localdef "static void bvifree(bvifile_t *fp) { 
  assert(fp); if (fp->base) free(fp->base); free(fp); }")
(%localdef "static int bviclose(bvifile_t *fp) { 
  assert(fp); if (fp->base) free(fp->base); fp->base = NULL; 
  fp->p = fp->e = (unsigned char *)\"\"; return 0; }")
(%localdef "static int bvigetch(bvifile_t *fp) {
  assert(fp && fp->p && fp->e); return (fp->p >= fp->e) ? EOF : (0xff & *(fp->p)++); }")
(%localdef "static int bviungetch(int c, bvifile_t *fp) {
  assert(fp && fp->p && fp->e); --(fp->p); assert(c == *(fp->p)); return c; }")
(%localdef "static cxtype_iport_t cxt_iport_bytevector = {
  \"bytevector-input-port\", (void (*)(void*))bvifree, (int (*)(void*))bviclose,
  (int (*)(void*))bvigetch, (int (*)(int, void*))bviungetch };")
(%localdef "cxtype_t *IPORT_BYTEVECTOR_NTAG = (cxtype_t *)&cxt_iport_bytevector;")
(%definition "#define mkiport_bytevector(l, fp) hpushptr(fp, IPORT_BYTEVECTOR_NTAG, l)")

(define-inline (open-input-bytevector s)
  (%prim*? "{ /* open-input-bytevector */
    int *d = dupbytevector(bytevectordata(obj_from_$arg));
    unsigned char *p = bvdatabytes(d), *e = p + *d;
    $return obj(mkiport_bytevector($live, bvialloc(p, e, d))); }" s))

; generic output ports

(%definition "/* output ports */")
(%definition "typedef struct { /* extends cxtype_t */
  const char *tname;
  void (*free)(void*);
  int (*close)(void*);
  int (*putch)(int, void*);
  int (*flush)(void*);
} cxtype_oport_t;")

(%definition "extern cxtype_t *OPORT_CLOSED_NTAG;")
(%definition "extern cxtype_t *OPORT_FILE_NTAG;")
(%definition "extern cxtype_t *OPORT_STRING_NTAG;")
(%definition "extern cxtype_t *OPORT_BYTEVECTOR_NTAG;")
(%definition "static cxtype_oport_t *oportvt(obj o) { 
  cxtype_t *pt; if (!isobjptr(o)) return NULL;
  pt = (cxtype_t*)objptr_from_obj(o)[-1];
  if (pt != OPORT_CLOSED_NTAG && pt != OPORT_FILE_NTAG && 
      pt != OPORT_STRING_NTAG && pt != OPORT_BYTEVECTOR_NTAG) return NULL; 
  else return (cxtype_oport_t*)pt; }")
(%definition "#define ckoportvt(o) ((cxtype_oport_t*)cxm_cknull(oportvt(o), \"oportvt\"))")  
(%definition "#define isoport(o) (oportvt(o) != NULL)")
(%definition "#define oportdata(o) ((void*)(*objptr_from_obj(o)))")

(%definition "static void oportputc(int c, obj o) {
  cxtype_oport_t *vt = oportvt(o); void *pp = oportdata(o);
  assert(vt); vt->putch(c, pp);
}")
(%definition "static void oportputs(char *s, obj o) {
  cxtype_oport_t *vt = oportvt(o); void *pp = oportdata(o);
  assert(vt); while (*s) vt->putch(*s++, pp);
}")
(%definition "static void oportwrite(char *s, int n, obj o) {
  cxtype_oport_t *vt = oportvt(o); void *pp = oportdata(o);
  assert(vt); while (n-- > 0) vt->putch(*s++, pp);
}")
(%definition "static void oportflush(obj o) {
  cxtype_oport_t *vt = oportvt(o); void *pp = oportdata(o);
  assert(vt); vt->flush(pp);
}")

(define-inline (output-port? x)
  (%prim "bool(isoport(obj_from_$arg))" x))

; closed output ports 

(%definition "/* closed output ports */")
(%localdef "static void cofree(void *p) {}")
(%localdef "static int coclose(void *p) { return 0; }")
(%localdef "static int coputch(int c, void *p) { return EOF; }")
(%localdef "static int coflush(void *p) { return EOF; }")
(%localdef "static cxtype_oport_t cxt_oport_closed = {
  \"closed-output-port\", (void (*)(void*))cofree, (int (*)(void*))coclose,
  (int (*)(int, void*))coputch, (int (*)(void*))coflush };")
(%localdef "cxtype_t *OPORT_CLOSED_NTAG = (cxtype_t *)&cxt_oport_closed;")

(define (close-output-port p)
  (%prim?! "{ /* close-output-port */
    obj o = obj_from_$arg; cxtype_oport_t *vt = oportvt(o); assert(vt);
    vt->close(oportdata(o)); vt->free(oportdata(o)); 
    objptr_from_obj(o)[-1] = (obj)OPORT_CLOSED_NTAG; 
    $return void(0); }" p)) 

(define-inline (output-port-open? p)
  (%prim? "bool(ckoportvt(obj_from_$arg) != (cxtype_oport_t *)OPORT_CLOSED_NTAG)" p))

; file output ports

(%localdef "static cxtype_oport_t cxt_oport_file = {
  \"file-output-port\", ffree, (int (*)(void*))fclose,
  (int (*)(int, void*))(fputc), (int (*)(void*))fflush };")
(%localdef "cxtype_t *OPORT_FILE_NTAG = (cxtype_t *)&cxt_oport_file;")
(%definition "#define mkoport_file(l, fp) hpushptr(fp, OPORT_FILE_NTAG, l)")

(define *current-output-port* (%prim* "obj(mkoport_file($live, stdout))"))

(define-syntax current-output-port ; parameter
  (syntax-rules ()
    [(_) *current-output-port*]
    [(_ p) (set! *current-output-port* p)]
    [(_ p s) (if s (set! *current-output-port* p) p)]
    [_ %residual-current-output-port]))

(define *current-error-port* (%prim* "obj(mkoport_file($live, stderr))"))

(define-syntax current-error-port ; parameter
  (syntax-rules ()
    [(_) *current-error-port*]
    [(_ p) (set! *current-error-port* p)]
    [(_ p s) (if s (set! *current-error-port* p) p)]
    [_ %residual-current-error-port]))

(define-inline (open-output-file fn)
  (let ([file* (open-file* fn "w")])
    (if file* (%prim*?! "obj(mkoport_file($live, (void*)(obj_from_$arg)))" file*)
        (file-error "cannot open output file" fn))))

(define-inline (open-binary-output-file fn)
  (let ([file* (open-file* fn "wb")])
    (if file* (%prim*?! "obj(mkoport_file($live, (void*)(obj_from_$arg)))" file*)
        (file-error "cannot open binary output file" fn))))

; string output ports 

(%definition "/* string output ports */")
(%definition "typedef struct cbuf_tag { char *buf; char *fill; char *end; } cbuf_t;")
(%definition "extern cbuf_t* newcb(void);") 
(%localdef "cbuf_t* newcb(void) {
  cbuf_t* pcb = cxm_cknull(malloc(sizeof(cbuf_t)), \"malloc(cbuf)\");
  pcb->fill = pcb->buf = cxm_cknull(malloc(64), \"malloc(cbdata)\");
  pcb->end = pcb->buf + 64; return pcb;
}")
(%definition "extern void freecb(cbuf_t* pcb);") 
(%localdef "void freecb(cbuf_t* pcb) { if (pcb) { free(pcb->buf); free(pcb); } }")
(%localdef "static void cbgrow(cbuf_t* pcb, size_t n) {
  size_t oldsz = pcb->end - pcb->buf, newsz = oldsz*2;
  size_t cnt = pcb->fill - pcb->buf;
  if (oldsz + n > newsz) newsz += n;
  pcb->buf = cxm_cknull(realloc(pcb->buf, newsz), \"realloc(cbdata)\");
  pcb->fill = pcb->buf + cnt, pcb->end = pcb->buf + newsz;
}")
(%definition "extern int cbputc(int c, cbuf_t* pcb);") 
(%localdef "int cbputc(int c, cbuf_t* pcb) {
  if ((pcb)->fill == (pcb)->end) cbgrow(pcb, 1); *((pcb)->fill)++ = c; return c;
}")
(%localdef "static int cbflush(cbuf_t* pcb) { return 0; }")
(%localdef "static int cbclose(cbuf_t* pcb) { free(pcb->buf); pcb->buf = NULL; return 0; }")
(%definition "extern size_t cblen(cbuf_t* pcb);")
(%localdef "size_t cblen(cbuf_t* pcb) { return pcb->fill - pcb->buf; }")
(%definition "extern char* cbdata(cbuf_t* pcb);") 
(%localdef "char* cbdata(cbuf_t* pcb) {
  if (pcb->fill == pcb->end) cbgrow(pcb, 1); *(pcb->fill) = 0; return pcb->buf; 
}")
(%localdef "static cxtype_oport_t cxt_oport_string = {
  \"string-output-port\", (void (*)(void*))freecb, (int (*)(void*))cbclose,
  (int (*)(int, void*))cbputc, (int (*)(void*))cbflush };")
(%localdef "cxtype_t *OPORT_STRING_NTAG = (cxtype_t *)&cxt_oport_string;")
(%definition "#define mkoport_string(l, fp) hpushptr(fp, OPORT_STRING_NTAG, l)")

(define-inline (open-output-string)
  (%prim*? "{ /* open-output-string */
    $return obj(mkoport_string($live, newcb())); }"))

(define-inline (get-output-string p) ; works on string and bv ports
  (%prim*? "{ /* get-output-string */
    obj o = obj_from_$arg; cxtype_oport_t *vt = ckoportvt(o); 
    if (vt != (cxtype_oport_t *)OPORT_STRING_NTAG &&
        vt != (cxtype_oport_t *)OPORT_BYTEVECTOR_NTAG) $return obj(mkeof());
    else { cbuf_t *pcb = oportdata(o); 
    $return obj(hpushstr($live, newstring(cbdata(pcb)))); } }" p)) 

; bytevector output ports 

(%definition "/* bytevector output ports */")
(%localdef "static cxtype_oport_t cxt_oport_bytevector = {
  \"bytevector-output-port\", (void (*)(void*))freecb, (int (*)(void*))cbclose,
  (int (*)(int, void*))cbputc, (int (*)(void*))cbflush };")
(%localdef "cxtype_t *OPORT_BYTEVECTOR_NTAG = (cxtype_t *)&cxt_oport_bytevector;")
(%definition "#define mkoport_bytevector(l, fp) hpushptr(fp, OPORT_BYTEVECTOR_NTAG, l)")

(define-inline (open-output-bytevector)
  (%prim*? "{ /* open-output-bytevector */
    $return obj(mkoport_bytevector($live, newcb())); }"))

(define-inline (get-output-bytevector p) ; works on bv and string ports
  (%prim*? "{ /* get-output-bytevector */
    obj o = obj_from_$arg; cxtype_oport_t *vt = ckoportvt(o); 
    if (vt != (cxtype_oport_t *)OPORT_BYTEVECTOR_NTAG &&
        vt != (cxtype_oport_t *)OPORT_STRING_NTAG) $return obj(mkeof());
    else { cbuf_t *pcb = oportdata(o); int len = (int)(pcb->fill - pcb->buf); 
    $return obj(hpushu8v($live, newbytevector((unsigned char *)pcb->buf, len))); } }" p)) 

; generic port predicates and standard opening/closing convenience ops

(define-inline (port? x) (or (input-port? x) (output-port? x)))
(define-syntax textual-port? port?) ; all ports are bimodal
(define-syntax binary-port? port?)  ; all ports are bimodal

(define (close-port p)
  (if (input-port? p) (close-input-port p))
  (if (output-port? p) (close-output-port p)))

; NB: call-with-port defined in the last section, after call-with-values

(define (call-with-input-file fname proc)
  (call-with-port (open-input-file fname) proc)) 

(define (call-with-output-file fname proc)
  (call-with-port (open-output-file fname) proc)) 

(define (with-input-from-port port thunk) ; extra
  (parameterize ([current-input-port port]) (thunk)))

(define (with-output-to-port port thunk) ; extra
  (parameterize ([current-output-port port]) (thunk)))

(define (with-input-from-file fname thunk)
  (call-with-input-file fname (lambda (p) (with-input-from-port p thunk))))

(define (with-output-to-file fname thunk)
  (call-with-output-file fname (lambda (p) (with-output-to-port p thunk))))

; simple text i/o

(define-syntax read-char
  (syntax-rules ()
    [(_) (read-char (current-input-port))]
    [(_ p) (%prim?! "{ int c = iportgetc(obj_from_$arg);  $return obj(c == EOF ? mkeof() : obj_from_char(c)); }" p)]
    [_ %residual-read-char]))

(define-syntax peek-char
  (syntax-rules ()
    [(_) (peek-char (current-input-port))]
    [(_ p) (%prim?! "{ int c = iportpeekc(obj_from_$arg);  $return obj(c == EOF ? mkeof() : obj_from_char(c)); }" p)]
    [_ %residual-peek-char]))

(define-syntax char-ready?
  (syntax-rules ()
    [(_) (char-ready? (current-input-port))]
    [(_ p) #t] ; no better solution for FILE/STRING ports
    [_ %residual-char-ready?]))

(define (%read-line p)
  (let ([op (open-output-string)])
    (let loop ([read-nothing? #t])
      (let ([c (read-char p)])
        (cond [(or (eof-object? c) (char=? c #\newline))
               (let ([s (get-output-string op)])
                 (close-output-port op) ; todo: use get-final-output-string
                 (if (and (eof-object? c) read-nothing?) c s))]
              [(char=? c #\return) (loop #f)]
              [else (%prim?! "void(oportputc(char_from_$arg, obj_from_$arg))" c op) (loop #f)]))))) 

(define-syntax read-line
  (syntax-rules ()
    [(_) (%read-line (current-input-port))]
    [(_ p) (%read-line p)]
    [_ %residual-read-line]))

(define (read-substring! str start end p)
  (let loop ([i start])
    (if (fx>=? i end)
        (fx- i start)
        (let ([c (read-char p)])
          (cond [(eof-object? c) (if (fx=? i start) c (fx- i start))]
                [else (string-set! str i c) (loop (fx+ i 1))])))))

(define (read-substring k p)
  (let ([str (make-string k)])
    (let ([r (read-substring! str 0 k p)])
      (if (eof-object? r)
          r
          (if (fx=? r k) str (substring str 0 r))))))

(define-syntax flush-output-port
  (syntax-rules ()
    [(_) (flush-output-port (current-output-port))]
    [(_ p) (%prim?! "void(oportflush(obj_from_$arg))" p)]
    [_ %residual-flush-output-port]))

(define-syntax write-char
  (syntax-rules ()
    [(_ c) (write-char c (current-output-port))]
    [(_ c p) (%prim?! "void(oportputc(char_from_$arg, obj_from_$arg))" c p)]
    [_ %residual-write-char]))

(define (write-substring from start end p)
  (do ([i start (fx+ i 1)]) [(fx>=? i end)] (write-char (string-ref from i) p)))

(define-syntax write-string
  (syntax-rules ()
    [(_ s) (write-string s (current-output-port))]
    [(_ s p) (%prim?! "void(oportputs(stringchars(obj_from_$arg), obj_from_$arg))" s p)]
    [(_ s p start) (let ([str s]) (write-substring str start (string-length str) p))]
    [(_ s p start end) (write-substring s start end p)]
    [_ %residual-write-string]))

(define-syntax newline
  (syntax-rules ()
    [(_) (newline (current-output-port))]
    [(_ p) (%prim?! "void(oportputc('\\n', obj_from_$arg))" p)]
    [_ %residual-newline]))

(define-syntax display-fixnum
  (syntax-rules ()
    [(_ x) (display-fixnum x (current-output-port))]
    [(_ x p) (%prim?! "{ /* display-fixnum */
    char buf[30]; sprintf(buf, \"%ld\", fixnum_from_$arg);
    $return void(oportputs(buf, obj_from_$arg)); }" x p)]
    [_ %residual-display-fixnum]))

(define-syntax display-flonum
  (syntax-rules ()
    [(_ x) (display-flonum x (current-output-port))]
    [(_ x p) (%prim?! "{ /* display-flonum */
    char buf[30], *s; double d = flonum_from_$arg; sprintf(buf, \"%.15g\", d);
    for (s = buf; *s != 0; s++) if (strchr(\".eE\", *s)) break;
    if (d != d) strcpy(buf, \"+nan.0\"); else if (d <= -HUGE_VAL) strcpy(buf, \"-inf.0\");
    else if (d >= HUGE_VAL) strcpy(buf, \"+inf.0\"); else if (*s == 'E') *s = 'e'; 
    else if (*s == 0) { *s++ = '.'; *s++ = '0'; *s = 0; }
    $return void(oportputs(buf, obj_from_$arg)); }" x p)]
    [_ %residual-display-flonum]))
    
(define-syntax display-procedure
  (syntax-rules ()
    [(_ x) (display-procedure x (current-output-port))]
    [(_ x p) (%prim?! "{ /* display-procedure */
    char buf[60]; sprintf(buf, \"#<procedure @%p>\", objptr_from_obj(obj_from_$arg));
    $return void(oportputs(buf, obj_from_$arg)); }" x p)]
    [_ %residual-display-procedure]))

(define-syntax display-input-port
  (syntax-rules ()
    [(_ x) (display-input-port x (current-output-port))]
    [(_ x p) (%prim?! "{ /* display-input-port */
    char buf[60]; sprintf(buf, \"#<%s>\", ckiportvt(obj_from_$arg)->tname);
    $return void(oportputs(buf, obj_from_$arg)); }" x p)]
    [_ %residual-display-input-port]))

(define-syntax display-output-port
  (syntax-rules ()
    [(_ x) (display-output-port x (current-output-port))]
    [(_ x p) (%prim?! "{ /* display-output-port */
    char buf[60]; sprintf(buf, \"#<%s>\", ckoportvt(obj_from_$arg)->tname);
    $return void(oportputs(buf, obj_from_$arg)); }" x p)]
    [_ %residual-display-output-port]))

; simple binary i/o

(define-syntax read-u8
  (syntax-rules ()
    [(_) (read-u8 (current-input-port))]
    [(_ p) (%prim?! "{ int c = iportgetc(obj_from_$arg);  $return obj(c == EOF ? mkeof() : obj_from_fixnum(c & 0xff)); }" p)]
    [_ %residual-read-u8]))

(define-syntax peek-u8
  (syntax-rules ()
    [(_) (peek-u8 (current-input-port))]
    [(_ p) (%prim?! "{ int c = iportpeekc(obj_from_$arg);  $return obj(c == EOF ? mkeof() : obj_from_fixnum(c & 0xff)); }" p)]
    [_ %residual-peek-char]))

(define-syntax u8-ready?
  (syntax-rules ()
    [(_) (u8-ready? (current-input-port))]
    [(_ p) #t] ; no better solution for FILE/STRING ports
    [_ %residual-u8-ready?]))

(define (read-subbytevector! vec start end p)
  (let loop ([i start])
    (if (fx>=? i end)
        (fx- i start)
        (let ([u8 (read-u8 p)])
          (cond [(eof-object? u8) (if (fx=? i start) u8 (fx- i start))]
                [else (bytevector-u8-set! vec i u8) (loop (fx+ i 1))])))))

(define (read-subbytevector k p)
  (let ([vec (make-bytevector k)])
    (let ([r (read-subbytevector! vec 0 k p)])
      (if (eof-object? r)
          r
          (if (fx=? r k) vec (subbytevector vec 0 r))))))

(define-syntax write-u8
  (syntax-rules ()
    [(_ c) (write-u8 c (current-output-port))]
    [(_ c p) (%prim?! "void(oportputc(fixnum_from_$arg, obj_from_$arg))" c p)]
    [_ %residual-write-u8]))

(define (write-subbytevector from start end p)
  (do ([i start (fx+ i 1)]) [(fx>=? i end)] (write-u8 (bytevector-u8-ref from i) p)))

(define-syntax write-bytevector
  (syntax-rules ()
    [(_ bv) (write-bytevector bv (current-output-port))]
    [(_ bv p) (%prim?! "{ /* write-bytevector */
    int *d = bytevectordata(obj_from_$arg);
    $return void(oportwrite((char *)bvdatabytes(d), *d,  obj_from_$arg)); }" bv p)]
    [(_ bv p start) (let ([vec bv]) (write-subbytevector vec start (bytevector-length vec) p))]
    [(_ bv p start end) (write-subbytevector bv start end p)]
    [_ %residual-write-bytevector]))


; circularity and sharing helpers

(%localdef "/* eq hash table for circular/sharing checks and safe equal? */
typedef struct { obj *v; obj *r; size_t sz; size_t u, maxu, c; } stab_t;
static stab_t *staballoc(void) {
  stab_t *p = cxm_cknull(calloc(1, sizeof(stab_t)), \"newstab\");
  p->v = cxm_cknull(calloc(64, sizeof(obj)), \"newstab[1]\");
  p->sz = 64, p->maxu = 64 / 2; return p;
}
static stab_t *stabfree(stab_t *p) { 
  if (p) { free(p->v); free(p->r); free(p); }
  return NULL; 
}
static int stabnew(obj o, stab_t *p, int circ) {
  if (!o || notaptr(o) || notobjptr(o) || (circ && isaptr(objptr_from_obj(o)[-1]))) return 0;
  else { /* v[i] is 0 or heap obj, possibly with lower bit set if it's not new */
    unsigned long h = (unsigned long)o; size_t sz = p->sz, i, j;
    for (i = h & (sz-1); p->v[i]; i = (i-1) & (sz-1))
      if ((p->v[i] & ~1) == o) { p->v[i] |= 1; return 0; }
    if (p->u == p->maxu) { /* rehash */
      size_t nsz = sz * 2; obj *nv = cxm_cknull(calloc(nsz, sizeof(obj)), \"stabnew\");
      for (i = 0; i < sz; ++i) if (p->v[i] & ~1) {
        for (j = (unsigned long)(p->v[i] & ~1) & (nsz-1); nv[j]; j = (j-1) & (nsz-1)) ;
        nv[j] = p->v[i];
      }
      free(p->v); p->v = nv; sz = p->sz = nsz; p->maxu = nsz / 2;
      for (i = h & (sz-1); p->v[i]; i = (i-1) & (sz-1)) ;
    }
    p->v[i] = o; p->u += 1; return 1; 
  }
}
static void stabdelifu(obj o, stab_t *p) { 
  unsigned long h = (unsigned long)o; size_t sz = p->sz, i;
  for (i = h & (sz-1); p->v[i]; i = (i-1) & (sz-1)) if ((p->v[i] & ~1) == o) { 
    if (p->v[i] & 1) /* keep */; else p->v[i] = 1; /* del */
    return;
  }
}
static void stabpushp(obj o, stab_t *p) {
  obj *r = p->r; if (!r) { p->r = r = cxm_cknull(calloc(sizeof(obj), 12), \"stabpushp\"); r[1] = 10; }
  else if (r[0] == r[1]) { p->r = r = cxm_cknull(realloc(r, sizeof(obj)*(2+r[1]*2)), \"stabpushp\"); r[1] *= 2; }
  r[2 + r[0]++] = o; 
}
static void stabpopp(stab_t *p) {
  obj *r = p->r; assert(r && r[0] > 0); r[0] -= 1;
}
static void stabcircular(obj o, stab_t *p) {
  tail: if (stabnew(o, p, 1)) {
    obj *op = objptr_from_obj(o), fo = op[-1];
    if (notaptr(fo)) { 
      obj *fop = op + size_from_obj(fo);
      stabpushp(0, p); while (op+1 < fop) stabcircular(*op++, p); stabpopp(p); 
      if (op+1 == fop) { stabpushp(o, p); o = *op; goto tail; }
    } 
  } else {
    obj *r = p->r; if (r) {
      obj *op = r+2, *fop = op+r[0];
      while (fop > op && fop[-1] != 0) stabdelifu(*--fop, p); 
      r[0] = fop - op;
    }
  }
}
static void stabshared(obj o, stab_t *p) {
  tail: if (stabnew(o, p, 0)) {
    obj *op = objptr_from_obj(o), fo = op[-1];
    if (notaptr(fo)) { 
      obj *fop = op + size_from_obj(fo); 
      while (op+1 < fop) stabshared(*op++, p);
      if (op+1 == fop) { o = *op; goto tail; }
    } 
  }
}
static stab_t *stabend(stab_t *p) {
  size_t nz, i, sz = p->sz;
  for (nz = i = 0; i < sz; ++i) if ((p->v[i] & ~1) && (p->v[i] & 1)) ++nz;
  if (nz) {
    size_t nsz, j; obj *nv; for (nsz = 8; nsz < nz*2; nsz *= 2) ;
    nv = cxm_cknull(calloc(nsz, sizeof(obj)), \"stabend\");
    for (i = 0; i < sz; ++i) if ((p->v[i] & ~1) && (p->v[i] & 1)) {
      for (j = (unsigned long)(p->v[i] & ~1) & (nsz-1); nv[j]; j = (j-1) & (nsz-1)) ;
      nv[j] = p->v[i];
    }
    free(p->v); p->v = nv; sz = p->sz = nsz; p->maxu = nsz / 2;
    free(p->r); p->r = NULL;
  } else p = stabfree(p);
  return p;
}
static long stabri(size_t i, stab_t *p, int upd) {
  obj *pri, ri; if (!p->r) p->r = cxm_cknull(calloc(p->sz, sizeof(obj)), \"stabri\");
  pri = p->r + i; ri = *pri; if (!ri) *pri = ri = ++(p->c);
  if (upd && ri > 0) *pri = -ri; return (long)ri;
}
static long stabref(obj o, stab_t *p, int upd) {
  if (!p || !o || notaptr(o) || notobjptr(o)) return 0; else {
    unsigned long h = (unsigned long)o; size_t sz = p->sz, i;
    for (i = h & (sz-1); p->v[i]; i = (i-1) & (sz-1))
      if ((p->v[i] & ~1) == o) return (p->v[i] & 1) ? stabri(i, p, upd) : 0; 
    return 0;
  }
}
static int stabufind(obj x, obj y, stab_t *p) {
  size_t sz = p->sz, i, ix=0, iy=0; /* bogus 0 inits to silence gcc */ obj *r = p->r;
  for (i = (unsigned long)x & (sz-1); p->v[i]; i = (i-1) & (sz-1)) if ((p->v[i] & ~1) == x) { ix = i; break; }
  for (i = ix; r[i] >= 0; ) i = (size_t)r[i]; if (i != ix) ix = r[ix] = i;  
  for (i = (unsigned long)y & (sz-1); p->v[i]; i = (i-1) & (sz-1)) if ((p->v[i] & ~1) == y) { iy = i; break; }
  for (i = iy; r[i] >= 0; ) i = (size_t)r[i]; if (i != iy) iy = r[iy] = i;
  if (ix == iy) return 1; /* same class, assumed to be equal */ 
  if (r[ix] < r[iy]) { r[ix] += r[iy]; r[iy] = ix; } else { r[iy] += r[ix]; r[ix] = iy; } return 0;
}
static int stabequal(obj x, obj y, stab_t *p) {
  obj h; int i, n; loop: if (x == y) return 1;
  if (!x || !y || notaptr(x) || notaptr(y) || notobjptr(x) || notobjptr(y)) return 0;
  if ((h = objptr_from_obj(x)[-1]) != objptr_from_obj(y)[-1]) return 0;
  if (h == (obj)FLONUM_NTAG) return flonum_from_obj(x) == flonum_from_obj(y); 
  if (h == (obj)STRING_NTAG) return strcmp(stringchars(x), stringchars(y)) == 0;
  if (h == (obj)BYTEVECTOR_NTAG) return bytevectoreq(bytevectordata(x), bytevectordata(y)); 
  if (isaptr(h) || !(n = size_from_obj(h)) || hblkref(x, 0) != hblkref(y, 0)) return 0;
  if (stabufind(x, y, p)) return 1; /* seen before and decided to be equal */
  for (i = 1; i < n-1; ++i) if (!stabequal(hblkref(x, i), hblkref(y, i), p)) return 0;
  if (i == n-1) { x = hblkref(x, i); y = hblkref(y, i); goto loop; } else return 1; 
}
static int boundequal(obj x, obj y, int fuel) { /* => remaining fuel or <0 on failure */
  obj h; int i, n; loop: assert(fuel > 0); if (x == y) return fuel-1;
  if (!x || !y || notaptr(x) || notaptr(y) || notobjptr(x) || notobjptr(y)) return -1;
  if ((h = objptr_from_obj(x)[-1]) != objptr_from_obj(y)[-1]) return -1;
  if (h == (obj)FLONUM_NTAG) return flonum_from_obj(x) == flonum_from_obj(y) ? fuel-1 : -1; 
  if (h == (obj)STRING_NTAG) return strcmp(stringchars(x), stringchars(y)) == 0 ? fuel-1 : -1;
  if (h == (obj)BYTEVECTOR_NTAG) return bytevectoreq(bytevectordata(x), bytevectordata(y)) ? fuel-1 : -1;
  if (isaptr(h) || !(n = size_from_obj(h)) || hblkref(x, 0) != hblkref(y, 0)) return -1;
  if (--fuel == 0) return 0; /* we must spend fuel while comparing objects themselves */
  for (i = 1; i < n-1; ++i) if ((fuel = boundequal(hblkref(x, i), hblkref(y, i), fuel)) <= 0) return fuel;
  if (i == n-1) { x = hblkref(x, i); y = hblkref(y, i); goto loop; } else return fuel;
}")


; circularity

(%definition "extern int iscircular(obj x);")
(%localdef "int iscircular(obj x) {
  if (!x || notaptr(x) || notobjptr(x)) return 0;
  else { stab_t *p = staballoc(); stabcircular(x, p); p = stabend(p); stabfree(p); return p != NULL; }
}")
(define-inline (circular? x)
  (%prim "bool(iscircular(obj_from_$arg))" x))


; equivalence and case

(%definition "extern int iseqv(obj x, obj y);")
(%localdef "int iseqv(obj x, obj y) {
  obj h; if (x == y) return 1;
  if (!x || !y || notaptr(x) || notaptr(y) || notobjptr(x) || notobjptr(y)) return 0;
  if ((h = objptr_from_obj(x)[-1]) != objptr_from_obj(y)[-1]) return 0;
  if (h == (obj)FLONUM_NTAG) return *(flonum_t*)objptr_from_obj(x)[0] == *(flonum_t*)objptr_from_obj(y)[0]; 
  return 0;
}")

(%definition "extern obj ismemv(obj x, obj l);")
(%localdef "obj ismemv(obj x, obj l) {
  if (!x || notaptr(x) || notobjptr(x)) {
    for (; l != mknull(); l = cdr(l)) 
      { if (car(l) == x) return l; }
  } else if (is_flonum_obj(x)) {
    flonum_t fx = flonum_from_obj(x); 
    for (; l != mknull(); l = cdr(l)) 
      { obj y = car(l); if (is_flonum_obj(y) && fx == flonum_from_obj(y)) return l; }
  } else { /* for others, memv == memq */
    for (; l != mknull(); l = cdr(l)) 
      { if (car(l) == x) return l; }
  } return 0;
}")

(%definition "extern obj isassv(obj x, obj l);")
(%localdef "obj isassv(obj x, obj l) {
  if (!x || notaptr(x) || notobjptr(x)) {
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l); if (car(p) == x) return p; }
  } else if (is_flonum_obj(x)) {
    flonum_t fx = flonum_from_obj(x); 
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l), y = car(p); if (is_flonum_obj(y) && fx == flonum_from_obj(y)) return p; }
  } else { /* for others, assv == assq */
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l); if (car(p) == x) return p; }
  } return 0;
}")

(%definition "extern int isequal(obj x, obj y);")
(%localdef "int isequal(obj x, obj y) {
  stab_t *p; obj *r; size_t i; int res = boundequal(x, y, 500);
  if (res != 0) return res > 0; /* small/non-circular/easy */
  p = staballoc(); stabshared(x, p); stabshared(y, p);
  r = p->r = cxm_cknull(calloc(p->sz, sizeof(obj)), \"isequal\");
  for (i = 0; i < p->sz; ++i) if (p->v[i] & ~1) r[i] = -1; 
  res = stabequal(x, y, p); stabfree(p); return res;
}")

(%definition "extern obj ismember(obj x, obj l);")
(%localdef "obj ismember(obj x, obj l) {
  if (!x || notaptr(x) || notobjptr(x)) {
    for (; l != mknull(); l = cdr(l)) 
      { if (car(l) == x) return l; }
  } else if (is_flonum_obj(x)) {
    flonum_t fx = flonum_from_obj(x); 
    for (; l != mknull(); l = cdr(l)) 
      { obj y = car(l); if (is_flonum_obj(y) && fx == flonum_from_obj(y)) return l; }
  } else if (isstring(x)) {
    char *xs = stringchars(x);
    for (; l != mknull(); l = cdr(l)) 
      { obj y = car(l); if (isstring(y) && 0 == strcmp(xs, stringchars(y))) return l; }
  } else {
    for (; l != mknull(); l = cdr(l)) 
      { if (isequal(car(l), x)) return l; }
  } return 0;
}")

(%definition "extern obj isassoc(obj x, obj l);")
(%localdef "obj isassoc(obj x, obj l) {
  if (!x || notaptr(x) || notobjptr(x)) {
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l); if (car(p) == x) return p; }
  } else if (is_flonum_obj(x)) {
    flonum_t fx = flonum_from_obj(x); 
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l), y = car(p); if (is_flonum_obj(y) && fx == flonum_from_obj(y)) return p; }
  } else if (isstring(x)) {
    char *xs = stringchars(x);
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l), y = car(p); if (isstring(y) && 0 == strcmp(xs, stringchars(y))) return p; }
  } else {
    for (; l != mknull(); l = cdr(l)) 
      { obj p = car(l); if (isequal(car(p), x)) return p; }
  } return 0;
}")

(define-inline (eq? x y)
  (%prim "bool(obj_from_$arg == obj_from_$arg)" x y))

(define-inline (eqv? x y)
  (or (eq? x y) ; covers fx=?
      (and (flonum? x) (flonum? y) (fl=? x y))))

(define-inline (equal? x y)
  (%prim? "bool(isequal(obj_from_$arg, obj_from_$arg))" x y))

(define-syntax case
  (letrec-syntax
    ([compare
      (syntax-rules ()
        [(_ key ()) #f]
        [(_ key (#&(id? datum) . data))
         (if (eq? key 'datum) #t (compare key data))]
        [(_ key (datum . data))
         (if (eqv? key 'datum) #t (compare key data))])]
     [case
      (syntax-rules (else =>)
        [(case key) (if #f #f)]
        [(case key (else => resproc))
         (resproc key)]
        [(case key (else result1 . results))
         (begin result1 . results)]
        [(case key ((datum ...) => resproc) . clauses)
         (if (compare key (datum ...))
             (resproc key)
             (case key . clauses))]
        [(case key ((datum ...) result1 . results) . clauses)
         (if (compare key (datum ...))
             (begin result1 . results)
             (case key . clauses))])])
     (syntax-rules ()
       [(_ expr clause1 clause ...)
        (let ([key expr]) (case key clause1 clause ...))])))



; equivalence-based member, assoc

(define-inline (memq x l)
  (%prim? "{ /* memq */
    obj x = obj_from_$arg, l = obj_from_$arg;
    for (; l != mknull(); l = cdr(l)) if (car(l) == x) break;
    $return obj(l == mknull() ? obj_from_bool(0) : l); }" x l)) 

(define-inline (memv x l)
  (%prim? "obj(ismemv(obj_from_$arg, obj_from_$arg))" x l)) 

(define-inline (meml x l)
  (%prim? "obj(ismember(obj_from_$arg, obj_from_$arg))" x l)) 

(define (%member x l eq) 
  (and (pair? l) (if (eq x (car l)) l (%member x (cdr l) eq))))

(define-syntax member
  (syntax-rules ()
    [(_ x l) (meml x l)]
    [(_ x l eq) (%member x l eq)]
    [_ %residual-member]))

(define-inline (assq x l)
  (%prim? "{ /* assq */
    obj x = obj_from_$arg, l = obj_from_$arg, p = mknull();
    for (; l != mknull(); l = cdr(l)) { p = car(l); if (car(p) == x) break; }
    $return obj(l == mknull() ? obj_from_bool(0) : p); }" x l)) 

(define-inline (assv x l)
  (%prim? "obj(isassv(obj_from_$arg, obj_from_$arg))" x l)) 

(define-inline (assl x l)
  (%prim? "obj(isassoc(obj_from_$arg, obj_from_$arg))" x l)) 

(define (%assoc x al eq) 
  (and (pair? al) (if (eq x (caar al)) (car al) (%assoc x (cdr al) eq))))

(define-syntax assoc
  (syntax-rules ()
    [(_ x al) (assl x al)]
    [(_ x al eq) (%assoc x al eq)]
    [_ %residual-assoc]))


; quasiquote

#read `<datum> as (quasiquote <datum>)
#read ,<datum> as (unquote <datum>)
#read ,@<datum> as (unquote-splicing <datum>)

(define-syntax quasiquote ; from eiod
  (syntax-rules (unquote unquote-splicing quasiquote)
    [(_ (unquote x)) x]
    [(_ ((unquote-splicing x))) x] ;esl: allow `(,@improper-list)
    [(_ ((unquote-splicing x) . y)) (append x (quasiquote y))]
    [(_ (quasiquote x) . d) (cons 'quasiquote (quasiquote (x) d))]
    [(_ (unquote x) d) (cons 'unquote (quasiquote (x) . d))]
    [(_ (unquote-splicing x) d) (cons 'unquote-splicing (quasiquote (x) . d))]
    [(_ (x . y) . d) (cons (quasiquote x . d) (quasiquote y . d))]
    [(_ #(x ...) . d) (list->vector (quasiquote (x ...) . d))]
    [(_ x . d) 'x]))


; S-expression writer

(%localdef "/* internal recursive write procedure */
typedef struct { stab_t *pst; int disp; cxtype_oport_t *vt; void *pp; } wenv_t;
static void wrc(int c, wenv_t *e) { e->vt->putch(c, e->pp); }
static void wrs(char *s, wenv_t *e) {
  cxtype_oport_t *vt = e->vt; void *pp = e->pp;
  assert(vt); while (*s) vt->putch(*s++, pp);
}
static int cleansymname(char *s) {
  char *inits = \"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!$%&*/:<=>?@^_~\";
  char *subss = \"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!$%&*/:<=>?@^_~0123456789.@+-\";
  if (s[0] == 0 || s[strspn(s, subss)] != 0) return 0; else if (strchr(inits, s[0])) return 1;
  else if (s[0] == '+' || s[0] == '-') return s[1] == 0 || (s[1] == '.' && s[2] && !isdigit(s[2])) || !isdigit(s[1]);
  else return s[0] == '.' && s[1] && !isdigit(s[1]); 
}
static void wrdatum(obj o, wenv_t *e) {
  long ref;
  tail: ref = stabref(o, e->pst, 1); /* update ref after access */
  if (ref < 0) { char buf[30]; sprintf(buf, \"#%ld#\", -ref-1); wrs(buf, e); return; }
  if (ref > 0) { char buf[30]; sprintf(buf, \"#%ld=\", +ref-1); wrs(buf, e); }
  if (is_bool_obj(o)) {
    wrs(bool_from_obj(o) ? \"#t\" : \"#f\", e);
  } else if (is_fixnum_obj(o)) {
    char buf[30]; sprintf(buf, \"%ld\", fixnum_from_obj(o)); wrs(buf, e);
  } else if (is_flonum_obj(o)) {
    char buf[30], *s; double d = flonum_from_obj(o); sprintf(buf, \"%.15g\", d);
    for (s = buf; *s != 0; s++) if (strchr(\".eE\", *s)) break;
    if (d != d) strcpy(buf, \"+nan.0\"); else if (d <= -HUGE_VAL) strcpy(buf, \"-inf.0\");
    else if (d >= HUGE_VAL) strcpy(buf, \"+inf.0\"); else if (*s == 'E') *s = 'e'; 
    else if (*s == 0) { *s++ = '.'; *s++ = '0'; *s = 0; }
    wrs(buf, e);
  } else if (iseof(o)) {
    wrs(\"#<eof>\", e);
  } else if (o == obj_from_void(0)) {
    wrs(\"#<void>\", e);
  } else if (o == obj_from_unit()) {
    wrs(\"#<values>\", e);
  } else if (isiport(o)) {
    char buf[60]; sprintf(buf, \"#<%s>\", ckiportvt(o)->tname); wrs(buf, e);
  } else if (isoport(o)) {
    char buf[60]; sprintf(buf, \"#<%s>\", ckoportvt(o)->tname); wrs(buf, e);
  } else if (issymbol(o)) {
    char *s = symbolname(getsymbol(o));
    if (e->disp || cleansymname(s)) wrs(s, e);
    else {
      wrc('|', e);
      while (*s) {
        int c = *s++;
        switch(c) {
          case '|': wrs(\"\\\\|\", e); break;
          case '\\\\': wrs(\"\\\\\\\\\", e); break;
          default: wrc(c, e); break;
        }
      }
      wrc('|', e);
    }

  } else if (isnull(o)) {
    wrs(\"()\", e);
  } else if (ispair(o)) {
    wrc('(', e); wrdatum(car(o), e);
    while (ispair(cdr(o)) && !stabref(cdr(o), e->pst, 0)) { wrc(' ', e); o = cdr(o);  wrdatum(car(o), e); }
    if (!isnull(cdr(o))) { wrs(\" . \", e); wrdatum(cdr(o), e); }
    wrc(')', e);
  } else if (is_char_obj(o)) {
    int c = char_from_obj(o);
    if (e->disp) wrc(c, e);
    else switch(c) {
      case 0x00: wrs(\"#\\\\null\", e); break;
      case 0x07: wrs(\"#\\\\alarm\", e); break;
      case 0x08: wrs(\"#\\\\backspace\", e); break;
      case 0x7f: wrs(\"#\\\\delete\", e); break;
      case 0x1b: wrs(\"#\\\\escape\", e); break;
      case '\\t': wrs(\"#\\\\tab\", e); break;
      case '\\n': wrs(\"#\\\\newline\", e); break;
      case '\\r': wrs(\"#\\\\return\", e); break;
      case ' ': wrs(\"#\\\\space\", e); break;
      default: wrs(\"#\\\\\", e); wrc(c, e); break;
    }
  } else if (isstring(o)) {
    char *s = stringchars(o);
    if (e->disp) wrs(s, e);
    else {
      wrc('\\\"', e);
      while (*s) {
        int c = *s++;
        switch(c) {
          case '\\\"': wrs(\"\\\\\\\"\", e); break;
          case '\\\\': wrs(\"\\\\\\\\\", e); break;
          default: wrc(c, e); break;
        }
      }
      wrc('\\\"', e);
    }
  } else if (isvector(o)) {
    int i, n = vectorlen(o);
    wrs(\"#(\", e);
    for (i = 0; i < n; ++i) { 
      if (i) wrc(' ', e); wrdatum(vectorref(o, i), e); 
    }
    wrc(')', e);
  } else if (isbytevector(o)) {
    int i, n = bytevectorlen(o);
    wrs(\"#u8(\", e);
    for (i = 0; i < n; ++i) { 
      char buf[30]; sprintf(buf, \"%d\", *bytevectorref(o, i));
      if (i) wrc(' ', e); wrs(buf, e); 
    }
    wrc(')', e);
  } else if (isbox(o)) {
    wrs(\"#&\", e); o = boxref(o); goto tail;
  } else if (istagged(o, 0)) {
    int i, n = taggedlen(o, 0);
    wrs(\"#<values\", e);
    for (i = 0; i < n; ++i) { 
      wrc(' ', e); wrdatum(*taggedref(o, 0, i), e); 
    }
    wrc('>', e);
  } else if (isprocedure(o)) {
    char buf[60]; sprintf(buf, \"#<procedure @%p>\", objptr_from_obj(o)); wrs(buf, e);
  } else if (isrecord(o)) {
    int i, n = recordlen(o);
    wrs(\"#<record \", e);
    wrdatum(recordrtd(o), e); // TODO: no need to show as shared!
    for (i = 0; i < n; ++i) { 
      wrc(' ', e); wrdatum(recordref(o, i), e); 
    }
    wrc('>', e);
  } else if (isvoid(o)) {
    wrs(\"#<void>\", e);
  } else {
    wrs(\"#<unknown>\", e);
  }
}")

(%definition "/* S-expression writers */
extern void oportputsimple(obj x, obj p, int disp);
extern void oportputcircular(obj x, obj p, int disp);
extern void oportputshared(obj x, obj p, int disp);")

(%localdef "/* S-expression writers */
void oportputsimple(obj x, obj p, int disp) {
  wenv_t e; e.pst = NULL; e.disp = disp; e.vt = oportvt(p); e.pp = oportdata(p);
  wrdatum(x, &e);
}
void oportputcircular(obj x, obj p, int disp) {
  wenv_t e; e.pst = staballoc(); e.disp = disp; e.vt = oportvt(p); e.pp = oportdata(p);
  stabcircular(x, e.pst); e.pst = stabend(e.pst);
  wrdatum(x, &e);
  stabfree(e.pst);
}
void oportputshared(obj x, obj p, int disp) {
  wenv_t e; e.pst = staballoc(); e.disp = disp; e.vt = oportvt(p); e.pp = oportdata(p);
  stabshared(x, e.pst); e.pst = stabend(e.pst);
  wrdatum(x, &e);
  stabfree(e.pst);
}")

(define-syntax write-simple
  (syntax-rules ()
    [(_ x) (%prim?! "void(oportputsimple(obj_from_$arg, obj_from_$arg, 0))" x (current-output-port))]
    [(_ x p) (%prim?! "void(oportputsimple(obj_from_$arg, obj_from_$arg, 0))" x p)]
    [_ %residual-write-simple]))

(define-syntax write-shared
  (syntax-rules ()
    [(_ x) (%prim?! "void(oportputshared(obj_from_$arg, obj_from_$arg, 0))" x (current-output-port))]
    [(_ x p) (%prim?! "void(oportputshared(obj_from_$arg, obj_from_$arg, 0))" x p)]
    [_ %residual-write-shared]))

(define-syntax write
  (syntax-rules ()
    [(_ x) (%prim?! "void(oportputcircular(obj_from_$arg, obj_from_$arg, 0))" x (current-output-port))]
    [(_ x p) (%prim?! "void(oportputcircular(obj_from_$arg, obj_from_$arg, 0))" x p)]
    [_ %residual-write]))

(define-syntax display
  (syntax-rules ()
    [(_ x) (%prim?! "void(oportputcircular(obj_from_$arg, obj_from_$arg, 1))" x (current-output-port))]
    [(_ x p) (%prim?! "void(oportputcircular(obj_from_$arg, obj_from_$arg, 1))" x p)]
    [_ %residual-display]))



; simple errors

(define (print-error-message prefix args ep)
  (define (pr-where args ep)
    (when (pair? args) 
      (cond [(not (car args)) 
             (write-string ": " ep)
             (pr-msg (cdr args) ep)]
            [(symbol? (car args)) 
             (write-string " in " ep) (write (car args) ep) (write-string ": " ep)
             (pr-msg (cdr args) ep)]
            [else 
             (write-string ": " ep)
             (pr-msg args ep)]))) 
  (define (pr-msg args ep)
    (when (pair? args) 
      (cond [(string? (car args))
             (display (car args) ep)
             (pr-rest (cdr args) ep)]
            [else (pr-rest args ep)])))
   (define (pr-rest args ep)
     (when (pair? args)
       (write-char #\space ep) (write (car args) ep)
       (pr-rest (cdr args) ep)))
   (cond [(or (string? prefix) (symbol? prefix)) 
          (write-string prefix ep)]
         [else (write-string "Error" ep)])
   (pr-where args ep)
   (newline ep))

(define (simple-error . args)
  (let ([ep (current-error-port)])
    (newline ep)
    (print-error-message "Error" args ep)
    (reset)))

(define (assertion-violation . args)
  (let ([ep (current-error-port)])
    (newline ep)
    (print-error-message "Assertion violation" args ep)
    (%prim! "{ assert(0); exit(1); $return void(0); }")))


; S-expression reader

(define (%read port simple?)

  (define-syntax r-error
    (syntax-rules () [(_ p msg a ...) (read-error msg a ... 'port: p)])) ; see read-error below

  (define shared '())
  (define (make-shared-ref loc) (lambda () (unbox loc)))
  (define (shared-ref? form) (procedure? form))
  (define (patch-ref! form) (if (procedure? form) (patch-ref! (form)) form))
  (define (patch-shared! form)
    (cond [(pair? form)
           (if (procedure? (car form)) 
               (set-car! form (patch-ref! (car form)))
               (patch-shared! (car form)))
           (if (procedure? (cdr form)) 
               (set-cdr! form (patch-ref! (cdr form)))
               (patch-shared! (cdr form)))]
          [(vector? form)
           (let loop ([i 0])
             (when (fx<? i (vector-length form))
               (let ([fi (vector-ref form i)])
                 (if (procedure? fi) 
                     (vector-set! form i (patch-ref! fi))
                     (patch-shared! fi)))
               (loop (fx+ i 1))))]
          [(box? form)
           (if (procedure? (unbox form))
               (set-box! form (patch-shared! (unbox form)))
               (patch-shared! (unbox form)))]))
  (define (patch-shared form) (patch-shared! form) form)           

  (define reader-token-marker #f)
  (define close-paren #f)
  (define close-bracket #f)
  (define dot #f)
  (define (let ([rtm (list 'reader-token)])
            (set! reader-token-marker rtm)
            (set! close-paren (cons rtm "right parenthesis"))
            (set! close-bracket (cons rtm "right bracket"))
            (set! dot (cons rtm "\" . \""))))

  (define (reader-token? form)
    (and (pair? form) (eq? (car form) reader-token-marker)))

  (define (char-symbolic? c)
    (string-position c
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!$%&*/:<=>?^_~0123456789+-.@"))

  (define (char-hex-digit? c)
    (let ([scalar-value (char->integer c)])
      (or (and (>= scalar-value 48) (<= scalar-value 57))
          (and (>= scalar-value 65) (<= scalar-value 70))
          (and (>= scalar-value 97) (<= scalar-value 102)))))

  (define (char-delimiter? c)
    (or (char-whitespace? c)
        (char=? c #\)) (char=? c #\()
        (char=? c #\]) (char=? c #\[)
        (char=? c #\") (char=? c #\;)))

  (define (sub-read-carefully p)
    (let ([form (sub-read p)])
      (cond [(eof-object? form)
             (r-error p "unexpected end of file")]
            [(reader-token? form) 
             (r-error p "unexpected token:" (cdr form))]
            [else form])))

  (define (sub-read p)
    (let ([c (read-char p)])
      (cond [(eof-object? c) c]
            [(char-whitespace? c) (sub-read p)]
            [(char=? c #\() (sub-read-list c p close-paren #t)]
            [(char=? c #\)) close-paren]
            [(char=? c #\[) (sub-read-list c p close-bracket #t)]
            [(char=? c #\]) close-bracket]
            [(char=? c #\') (list 'quote (sub-read-carefully p))]
            [(char=? c #\`) (list 'quasiquote (sub-read-carefully p))]
            [(char-symbolic? c) (sub-read-number-or-symbol c p)]
            [(char=? c #\;)
             (let loop ([c (read-char p)])
               (or (eof-object? c) (char=? c #\newline)
                   (loop (read-char p))))
             (sub-read p)]
            [(char=? c #\,)
             (let ([next (peek-char p)])
               (cond [(eof-object? next)
                      (r-error p "end of file after ,")]
                     [(char=? next #\@)
                      (read-char p)
                      (list 'unquote-splicing (sub-read-carefully p))]
                     [else (list 'unquote (sub-read-carefully p))]))]
            [(char=? c #\")
             (let loop ([l '()])
               (let ([c (read-char p)])
                 (cond [(eof-object? c)
                        (r-error p "end of file within a string")]
                       [(char=? c #\\)
                        (let ([e (sub-read-strsym-char-escape p 'string)])
                          (loop (if e (cons e l) l)))]
                       [(char=? c #\") (list->string (reverse! l))]
                       [else (loop (cons c l))])))]
            [(char=? c #\|)
             (let loop ([l '()])
               (let ([c (read-char p)])
                 (cond [(eof-object? c)
                        (r-error p "end of file within a |symbol|")]
                       [(char=? c #\\)
                        (let ([e (sub-read-strsym-char-escape p 'symbol)])
                          (loop (if e (cons e l) l)))]
                       [(char=? c #\|) (string->symbol (list->string (reverse! l)))]
                       [else (loop (cons c l))])))]
            [(char=? c #\#)
             (let ([c (peek-char p)])
               (cond [(eof-object? c) (r-error p "end of file after #")]
                     [(or (char-ci=? c #\t) (char-ci=? c #\f))
                      (let ([name (sub-read-carefully p)])
                        (case name [(t true) #t] [(f false) #f]
                          [else (r-error p "unexpected name after #" name)]))]
                     [(or (char-ci=? c #\b) (char-ci=? c #\o)
                          (char-ci=? c #\d) (char-ci=? c #\x)
                          (char-ci=? c #\i) (char-ci=? c #\e))
                      (sub-read-number-or-symbol #\# p)]
                     [(char=? c #\&)
                      (read-char p)
                      (box (sub-read-carefully p))]
                     [(char=? c #\;)
                      (read-char p)
                      (sub-read-carefully p) 
                      (sub-read p)]
                     [(char=? c #\|)
                      (read-char p)
                      (let recur () ;starts right after opening #|
                        (let ([next (read-char p)])
                          (cond
                            [(eof-object? next)
                             (r-error p "end of file in #| comment")]
                            [(char=? next #\|)
                             (let ([next (peek-char p)])
                               (cond
                                 [(eof-object? next)
                                  (r-error p "end of file in #| comment")]
                                 [(char=? next #\#) (read-char p)]
                                 [else (recur)]))]
                            [(char=? next #\#)
                             (let ([next (peek-char p)])
                               (cond
                                 [(eof-object? next)
                                  (r-error p "end of file in #| comment")]
                                 [(char=? next #\|) (read-char p) (recur) (recur)]
                                 [else (recur)]))]
                            [else (recur)])))
                      (sub-read p)]
                     [(char=? c #\() ;)
                      (read-char p)
                      (list->vector (sub-read-list c p close-paren #f))]
                     [(char=? c #\u)
                      (read-char p)
                      (if (and (eq? (read-char p) #\8) (eq? (read-char p) #\())
                          (list->bytevector (sub-read-byte-list p))
                          (r-error p "invalid bytevector syntax"))]
                     [(char=? c #\\)
                      (read-char p)
                      (let ([c (peek-char p)])
                        (cond
                          [(eof-object? c)
                           (r-error p "end of file after #\\")]
                          [(char=? #\x c)
                           (read-char p)
                           (if (char-delimiter? (peek-char p))
                               c
                               (sub-read-x-char-escape p #f))]
                          [(char-alphabetic? c)
                           (let ([name (sub-read-carefully p)])
                             (if (= (string-length (symbol->string name)) 1)
                                 c
                                 (case name
                                   [(null) (integer->char #x00)]
                                   [(space) #\space]
                                   [(alarm) #\alarm]
                                   [(backspace) #\backspace]
                                   [(delete) (integer->char #x7F)] ; todo: support by SFC
                                   [(escape) (integer->char #x1B)]
                                   [(tab) #\tab]
                                   [(newline linefeed) #\newline]
                                   [(vtab) #\vtab]
                                   [(page) #\page]
                                   [(return) #\return]
                                   [else (r-error p "unknown #\\ name" name)])))]
                          [else (read-char p) c]))]
                     [(char-numeric? c)
                      (when simple? (r-error p "#N=/#N# notation is not allowed in this mode")) 
                      (let loop ([l '()])
                        (let ([c (read-char p)])
                          (cond [(eof-object? c)
                                 (r-error p "end of file within a #N notation")]
                                [(char-numeric? c)
                                 (loop (cons c l))]
                                [(char=? c #\#) 
                                 (let* ([s (list->string (reverse! l))] [n (string->number s)])
                                   (cond [(and (fixnum? n) (assq n shared)) => cdr]
                                         [else (r-error "unknown #n# reference:" s)]))]   
                                [(char=? c #\=) 
                                 (let* ([s (list->string (reverse! l))] [n (string->number s)])
                                   (cond [(not (fixnum? n)) (r-error "invalid #n= reference:" s)]
                                         [(assq n shared) (r-error "duplicate #n= tag:" n)])
                                   (let ([loc (box #f)])
                                     (set! shared (cons (cons n (make-shared-ref loc)) shared))
                                     (let ([form (sub-read-carefully p)])
                                       (cond [(shared-ref? form) (r-error "#n= has another label as target" s)]
                                             [else (set-box! loc form) form]))))]
                                [else (r-error p "invalid terminator for #N notation")])))]
                     [else (r-error p "unknown # syntax" c)]))]
            [else (r-error p "illegal character read" c)])))

  (define (sub-read-list c p close-token dot?)
    (let ([form (sub-read p)])
      (if (eq? form dot)
          (r-error p "missing car -- ( immediately followed by .") ;)
          (let recur ([form form])
            (cond [(eof-object? form)
                   (r-error p "eof inside list -- unbalanced parentheses")]
                  [(eq? form close-token) '()]
                  [(eq? form dot)
                   (if dot?
                       (let* ([last-form (sub-read-carefully p)]
                              [another-form (sub-read p)])
                         (if (eq? another-form close-token)
                             last-form
                             (r-error p "randomness after form after dot" another-form)))
                       (r-error p "dot in #(...)"))]
                  [(reader-token? form)
                   (r-error p "error inside list --" (cdr form))]
                  [else (cons form (recur (sub-read p)))])))))

  (define (sub-read-byte-list p)
    (let recur ([form (sub-read p)])
      (cond [(eof-object? form)
              (r-error p "eof inside bytevector")]
            [(eq? form close-paren) '()]
            [(reader-token? form)
              (r-error p "error inside bytevector --" (cdr form))]
            [(or (not (fixnum? form)) (fx<? form 0) (fx>? form 255))
              (r-error p "invalid byte inside bytevector --" form)]
            [else (cons form (recur (sub-read p)))])))

  (define (sub-read-strsym-char-escape p what)
    (let ([c (read-char p)])
      (if (eof-object? c)
          (r-error p "end of file within a" what))
      (cond [(or (char=? c #\\) (char=? c #\") (char=? c #\|)) c]
            [(char=? c #\a) #\alarm]
            [(char=? c #\b) #\backspace]
            [(char=? c #\t) #\tab]
            [(char=? c #\n) #\newline]
            [(char=? c #\v) #\vtab]
            [(char=? c #\f) #\page]
            [(char=? c #\r) #\return]
            [(char=? c #\x) (sub-read-x-char-escape p #t)]
            [(and (eq? what 'string) (char-whitespace? c))
             (let loop ([gotnl (char=? c #\newline)] [nc (peek-char p)])
               (cond [(or (eof-object? nc) (not (char-whitespace? nc)))
                      (if gotnl #f (r-error p "no newline in line ending escape"))]
                     [(and gotnl (char=? nc #\newline)) #f]
                     [else (read-char p) (loop (or gotnl (char=? nc #\newline)) (peek-char p))]))]
            [else (r-error p "invalid char escape in" what ': c)])))

  (define (sub-read-x-char-escape p in-string?)
    (define (rev-digits->char l)
      (if (null? l)
          (r-error p "\\x escape sequence is too short")
          (integer->char (string->fixnum (list->string (reverse! l)) 16))))
    (let loop ([c (peek-char p)] [l '()] [cc 0])
      (cond [(eof-object? c)
             (if in-string?
               (r-error p "end of file within a string")
               (rev-digits->char l))]
            [(and in-string? (char=? c #\;))
             (read-char p)
             (rev-digits->char l)]
            [(and (not in-string?) (char-delimiter? c))
             (rev-digits->char l)]
            [(not (char-hex-digit? c))
             (r-error p "unexpected char in \\x escape sequence" c)]
            [(> cc 2)
             (r-error p "\\x escape sequence is too long")]
            [else
             (read-char p)
             (loop (peek-char p) (cons c l) (+ cc 1))])))

  (define (suspect-number-or-symbol-peculiar? hash? c l s)
    (cond [(or hash? (char-numeric? c)) #f]
          [(or (string-ci=? s "+i") (string-ci=? s "-i")) #f]
          [(or (string-ci=? s "+nan.0") (string-ci=? s "-nan.0")) #f]
          [(or (string-ci=? s "+inf.0") (string-ci=? s "-inf.0")) #f]
          [(or (char=? c #\+) (char=? c #\-))
           (cond [(null? (cdr l)) #t]
                 [(char=? (cadr l) #\.) (and (pair? (cddr l)) (not (char-numeric? (caddr l))))]
                 [else (not (char-numeric? (cadr l)))])]
          [else (and (char=? c #\.) (pair? (cdr l)) (not (char-numeric? (cadr l))))]))

  (define (sub-read-number-or-symbol c p)
    (let loop ([c (peek-char p)] [l (list c)] [hash? (char=? c #\#)])
      (cond [(or (eof-object? c) (char-delimiter? c))
             (let* ([l (reverse! l)] [c (car l)] [s (list->string l)])
               (if (or hash? (char-numeric? c) 
                     (char=? c #\+) (char=? c #\-) (char=? c #\.))   
                   (cond [(string=? s ".") dot]
                         [(suspect-number-or-symbol-peculiar? hash? c l s) (string->symbol s)]
                         [(string->number s)]
                         [else (r-error p "unsupported number syntax (implementation restriction)" s)])
                   (string->symbol s)))]
            [(char=? c #\#)
             (read-char p) 
             (loop (peek-char p) (cons c l) #t)]
            [(char-symbolic? c)
             (read-char p) 
             (loop (peek-char p) (cons c l) hash?)]
            [else (r-error p "unexpected number/symbol char" c)])))
            
  ; body of %read
  (let ([form (sub-read port)])
    (if (not (reader-token? form))
        (if (null? shared) form (patch-shared form))
        (r-error port "unexpected token:" (cdr form)))))

(define-syntax read
  (syntax-rules ()
    [(_) (%read (current-input-port) #f)]
    [(_ p) (%read p #f)]
    [_ %residual-read]))

(define-syntax read-simple
  (syntax-rules ()
    [(_) (%read (current-input-port) #t)]
    [(_ p) (%read p #t)]
    [_ %residual-read-simple]))


; file system

(define (file-exists? fn) ; fixme?
  (%prim?! "{ /* file-exists? */ 
    FILE *f = fopen(stringchars(obj_from_$arg), \"r\");
    if (f != NULL) fclose(f);
    $return bool(f != NULL); }" fn))

(define (delete-file fn)
  (unless (%prim?! "{ /* delete-file */ 
    int res = remove(stringchars(obj_from_$arg));
    $return bool(res == 0); }" fn)
    (file-error "cannot delete file:" fn)))

(define (rename-file fnold fnnew) ; not in r7rs
  (unless (%prim?! "{ /* rename-file */ 
    int res = rename(stringchars(obj_from_$arg), stringchars(obj_from_$arg));
    $return bool(res == 0); }" fnold fnnew)
    (file-error "cannot rename file:" fnold fnnew)))



; multiple values & continuations

(define-inline (call-with-values producer consumer)
  (letcc k
    (withcc 
      (lambda results
        (withcc k (apply consumer results)))
      (producer))))

(define *current-dynamic-state* (list #f))

(define (call-with-current-continuation proc)
  (let ([here *current-dynamic-state*])
    (letcc cont
      (proc 
        (lambda results
           (dynamic-state-reroot! here)
           (apply cont results))))))

(define-syntax call/cc call-with-current-continuation)

(define-syntax throw
  (syntax-rules ()
    [(_ k expr ...) 
     (withcc (%prim "ktrap()") (k expr ...))]))

(define-syntax values
  (syntax-rules ()
    [(_ expr ...) 
     (call/cc (lambda (k) (throw k expr ...)))]
    [_ %residual-values]))

(define (dynamic-wind before during after)
  (let ([here *current-dynamic-state*])
    (dynamic-state-reroot! (cons (cons before after) here))
    (call-with-values during
      (lambda results
        (dynamic-state-reroot! here)
        (apply values results)))))

(define (dynamic-state-reroot! there)
  (if (not (eq? *current-dynamic-state* there))
      (begin (dynamic-state-reroot! (cdr there))
             (let ([before (caar there)] [after (cdar there)])
               (set-car! *current-dynamic-state* (cons after before))
               (set-cdr! *current-dynamic-state* there)
               (set-car! there #f)
               (set-cdr! there '())
               (set! *current-dynamic-state* there)
               (before)))))


; exceptions and errors

(define-record-type <error-object>
  (error-object kind message irritants)
  error-object?
  (kind error-object-kind)
  (message error-object-message)
  (irritants error-object-irritants))

(define (error msg . args)
  (raise (error-object #f msg args)))

(define current-exception-handler 
  (make-parameter
    (letrec 
      ([default-handler
        (case-lambda 
          [() default-handler] ;this one its own parent 
          [(obj) 
           (if (error-object? obj)
               (apply simple-error (error-object-kind obj) (error-object-message obj) (error-object-irritants obj)) 
               (simple-error #f "unhandled exception" obj))])])
      default-handler)))

(define (with-exception-handler handler thunk)
  (let ([eh (current-exception-handler)])
    (parameterize ([current-exception-handler (case-lambda [() eh] [(obj) (handler obj)])])
      (thunk)))) 

(define (raise obj)
  (let ([eh (current-exception-handler)])
    (parameterize ([current-exception-handler (eh)])
      (eh obj)
      (raise (error-object 'raise "exception handler returned" (list eh obj))))))

(define (raise-continuable obj)
  (let ([eh (current-exception-handler)])
    (parameterize ([current-exception-handler (eh)])
      (eh obj))))

(define-inline (abort) (%prim! "void(exit(1))"))
(define (reset) (%prim! "void(exit(1))"))
(define (set-reset-handler! fn) (set! reset fn))

(define-syntax guard
  (letrec-syntax
    ([guard-aux
      (syntax-rules (else =>)
        [(guard-aux reraise (else result1 result2 ...))
        (begin result1 result2 ...)]
        [(guard-aux reraise (test => result))
        (let ([temp test]) (if temp (result temp) reraise))]
        [(guard-aux reraise (test => result) clause1 clause2 ...)
        (let ([temp test])
          (if temp
              (result temp)
              (guard-aux reraise clause1 clause2 ...)))]
        [(guard-aux reraise (test)) (or test reraise)]
        [(guard-aux reraise (test) clause1 clause2 ...)
        (let ([temp test])
          (if temp temp (guard-aux reraise clause1 clause2 ...)))]
        [(guard-aux reraise (test result1 result2 ...))
        (if test (begin result1 result2 ...) reraise)]
        [(guard-aux reraise (test result1 result2 ...) clause1 clause2 ...)
        (if test
            (begin result1 result2 ...)
            (guard-aux reraise clause1 clause2 ...))])])
    (syntax-rules ()
      [(guard (var clause ...) e1 e2 ...)
      ((call/cc
        (lambda (guard-k)
          (with-exception-handler
            (lambda (condition)
              ((call/cc
                  (lambda (handler-k)
                    (guard-k
                      (lambda ()
                        (let ([var condition])
                          (guard-aux
                            (handler-k
                              (lambda ()
                                (raise-continuable condition)))
                            clause
                            ...))))))))
            (lambda ()
              (call-with-values
                (lambda () e1 e2 ...)
                (lambda args
                  (guard-k (lambda () (apply values args))))))))))])))


(define (read-error msg . args)
  (raise (error-object 'read msg args)))

(define (read-error? obj)
  (and (error-object? obj) (eq? (error-object-kind obj) 'read))) 

(define (file-error msg . args)
  (raise (error-object 'file msg args)))

(define (file-error? obj)
  (and (error-object? obj) (eq? (error-object-kind obj) 'file))) 


; time

(%include <time.h>)

(define-inline (current-jiffy)
  (%prim*! "flonum($live, clock())"))

(define-inline (jiffies-per-second)
  (%prim* "flonum($live, CLOCKS_PER_SEC)"))

(define-inline (current-second)
  (%prim* "flonum($live, difftime(time(NULL), 0)+37.0)"))


; miscellaneous / system

(define emergency-exit  
  (case-lambda ; exits no matter what
    [() (%prim! "void(exit(0))")]
    [(n) (cond [(eq? n #t) (%prim! "void(exit(0))")] 
               [(fixnum? n) (%prim! "void(exit(fixnum_from_$arg))" n)]
               [else (%prim! "void(exit(1))")])]
    [args (%prim! "void(exit(1))")]))

(define exit 
  (let ([exit-ds *current-dynamic-state*])
    (lambda args
      (dynamic-state-reroot! exit-ds)
      (apply emergency-exit args))))    

(define-inline (argv-ref argv i)
  (%prim* "{ /* argv-ref */
    int i = fixnum_from_$arg;
    char *s = ((char **)(obj_from_$arg))[i];
    if (s) $return obj(hpushstr($live, newstring(s)));
    else $return bool(0); }" i argv))

(define (command-line)
  (let loop ([r '()] [i (%prim "fixnum(0)")])
    (let ([arg (argv-ref (%prim "obj(cxg_argv)") i)])
      (if arg 
          (loop (cons arg r) (fx+ i (%prim "fixnum(1)")))
          (reverse! r)))))

(define-inline (get-environment-variable s)
  (%prim*? "{ /* get-environment-variable */
    char *v = getenv(stringchars(obj_from_$arg));
    if (v) $return obj(hpushstr($live, newstring(v)));
    else $return bool(0); }" s))

(define-inline (system cmd)
  (%prim?! "{ /* system */
    int res = system(stringchars(obj_from_$arg));
    $return fixnum(res); }" cmd))


;------------------------------------------------------------------------------

; stubs

(define-inline (make-rectangular r i)
  (if (= i 0) r (error 'make-rectangular "nonzero imag part not supported" i)))
(define-inline (make-polar m a)
  (cond [(= a 0) m]
        [(= a 3.141592653589793238462643) (- m)]
        [else (error 'make-polar "angle not supported" a)]))
(define-inline (real-part x) x)
(define-inline (imag-part x) 0)
(define-inline (magnitude x) (abs x))
(define-inline (angle x) (if (negative? x) 3.141592653589793238462643 0))


; procedures requiring call-with-values / values

(define (truncate/ x y)
  (values (truncate-quotient x y) (truncate-remainder x y)))

(define (floor/ x y)
  (values (floor-quotient x y) (floor-remainder x y)))

(define (exact-integer-sqrt x)
  (let ([r (fxsqrt x)])
    (values r (- x (* r r)))))

(define (call-with-port port proc)
  (call-with-values (lambda () (proc port))
    (lambda vals (close-port port) (apply values vals))))


; procedures of variable arity (plain and making use of case-lambda)

(define string->list
  (case-lambda
     [(str) (substring->list str 0 (string-length str))]
     [(str start) (substring->list str start (string-length str))]
     [(str start end) (substring->list str start end)]))

(define string-copy 
  (case-lambda
     [(str) (%string-copy str)]
     [(str start) (substring str start (string-length str))]
     [(str start end) (substring str start end)]))

(define string-copy!
  (case-lambda
     [(to at from) (substring-copy! to at from 0 (string-length from))]
     [(to at from start) (substring-copy! to at from start (string-length from))]
     [(to at from start end) (substring-copy! to at from start end)]))

(define string-fill!
  (case-lambda
     [(str c) (%string-fill! str c)]
     [(str c start) (substring-fill! str c start (string-length str))]
     [(str c start end) (substring-fill! str c start end)]))

(define vector->list
  (case-lambda
     [(vec) (subvector->list vec 0 (vector-length vec))]
     [(vec start) (subvector->list vec start (vector-length vec))]
     [(vec start end) (subvector->list vec start end)]))

(define vector->string
  (case-lambda
     [(vec) (subvector->string vec 0 (vector-length vec))]
     [(vec start) (subvector->string vec start (vector-length vec))]
     [(vec start end) (subvector->string vec start end)]))

(define string->vector
  (case-lambda
     [(str) (substring->vector str 0 (string-length str))]
     [(str start) (substring->vector str start (string-length str))]
     [(str start end) (substring->vector str start end)]))

(define vector-copy!
  (case-lambda
     [(to at from) (subvector-copy! to at from 0 (vector-length from))]
     [(to at from start) (subvector-copy! to at from start (vector-length from))]
     [(to at from start end) (subvector-copy! to at from start end)]))

(define vector-copy
  (case-lambda
     [(vec) (subvector vec 0 (vector-length vec))]
     [(vec start) (subvector vec start (vector-length vec))]
     [(vec start end) (subvector vec start end)]))

(define (%vectors-sum-length vecs)
  (let loop ([vecs vecs] [l 0])
    (if (null? vecs) l (loop (cdr vecs) (fx+ l (vector-length (car vecs)))))))

(define (%vectors-copy-into! to vecs)
  (let loop ([vecs vecs] [i 0])
    (if (null? vecs)
        to
        (let ([vec (car vecs)] [vecs (cdr vecs)])
          (let ([len (vector-length vec)])
            (subvector-copy! to i vec 0 len)
            (loop vecs (fx+ i len)))))))  

(define (vector-append . vecs)
  (%vectors-copy-into! (make-vector (%vectors-sum-length vecs)) vecs))

(define vector-fill!
  (case-lambda
     [(vec x) (subvector-fill! vec x 0 (vector-length vec))]
     [(vec x start) (subvector-fill! vec x start (vector-length vec))]
     [(vec x start end) (subvector-fill! vec x start end)]))

(define bytevector->list
  (case-lambda
     [(vec) (subbytevector->list vec 0 (bytevector-length vec))]
     [(vec start) (subbytevector->list vec start (bytevector-length vec))]
     [(vec start end) (subbytevector->list vec start end)]))

(define bytevector-copy!
  (case-lambda
     [(to at from) (subbytevector-copy! to at from 0 (bytevector-length from))]
     [(to at from start) (subbytevector-copy! to at from start (bytevector-length from))]
     [(to at from start end) (subbytevector-copy! to at from start end)]))

(define bytevector-copy
  (case-lambda
     [(vec) (subbytevector vec 0 (bytevector-length vec))]
     [(vec start) (subbytevector vec start (bytevector-length vec))]
     [(vec start end) (subbytevector vec start end)]))

(define (%bytevectors-sum-length vecs)
  (let loop ([vecs vecs] [l 0])
    (if (null? vecs) l (loop (cdr vecs) (fx+ l (bytevector-length (car vecs)))))))

(define (%bytevectors-copy-into! to vecs)
  (let loop ([vecs vecs] [i 0])
    (if (null? vecs)
        to
        (let ([vec (car vecs)] [vecs (cdr vecs)])
          (let ([len (bytevector-length vec)])
            (subbytevector-copy! to i vec 0 len)
            (loop vecs (fx+ i len)))))))  

(define (bytevector-append . vecs)
  (%bytevectors-copy-into! (make-bytevector (%bytevectors-sum-length vecs)) vecs))

(define (subutf8->string vec start end)
  (let ([p (open-output-string)])
    (write-subbytevector vec start end p)
    ; todo: make a single operation: get-final-output-string (can reuse cbuf?)
    (let ([s (get-output-string p)]) (close-output-port p) s)))

(define utf8->string
  (case-lambda
    [(vec) (%prim*? "{ /* bytevector->string */
    int *d = bytevectordata(obj_from_$arg);
    $return obj(hpushstr($live, newstringn((char *)bvdatabytes(d), *d))); }" vec)]
    [(vec start) (subutf8->string vec start (bytevector-length vec))]
    [(vec start end) (subutf8->string vec start end)]))

(define (substring->utf8 str start end)
  (let ([p (open-output-bytevector)])
    (write-substring str start end p)
    ; todo: make a single operation: get-final-output-bytevector (can reuse cbuf?)
    (let ([v (get-output-bytevector p)]) (close-output-port p) v)))

(define string->utf8
  (case-lambda
    [(str) (%prim*? "{ /* string->bytevector */
    int *d = stringdata(obj_from_$arg);
    $return obj(hpushu8v($live, newbytevector((unsigned char *)sdatachars(d), *d))); }" str)]
    [(str start) (substring->utf8 str start (string-length str))]
    [(str start end) (substring->utf8 str start end)]))

(define read-string!
  (case-lambda
    [(str) (read-substring! str 0 (string-length str) (current-input-port))]
    [(str p) (read-substring! str 0 (string-length str) p)]
    [(str p start) (read-substring! str start (string-length str) p)]
    [(str p start end) (read-substring! str start end p)]))

(define read-string
  (case-lambda
    [(k) (read-substring k (current-input-port))]
    [(k p) (read-substring k p)]))

(define read-bytevector!
  (case-lambda
    [(vec) (read-subbytevector! vec 0 (bytevector-length vec) (current-input-port))]
    [(vec p) (read-subbytevector! vec 0 (bytevector-length vec) p)]
    [(vec p start) (read-subbytevector! vec start (bytevector-length vec) p)]
    [(vec p start end) (read-subbytevector! vec start end p)]))

(define read-bytevector
  (case-lambda
    [(k) (read-subbytevector k (current-input-port))]
    [(k p) (read-subbytevector k p)]))


; residual versions of inline procedures

(define (%residual-values . l)
  (call/cc (lambda (k) (throw apply k l))))

(define-syntax cmp-reducer
  (syntax-rules ()
    [(_ f)
     (lambda args
       (or (null? args)
           (let loop ([x (car args)] [args (cdr args)])
             (or (null? args)
                 (let ([y (car args)])
                   (and (f x y) (loop y (cdr args))))))))]))

(define %residual-boolean=? (cmp-reducer boolean=?))  

(define %residual-fx=? (cmp-reducer fx=?))
(define %residual-fx<? (cmp-reducer fx<?))
(define %residual-fx>? (cmp-reducer fx>?))
(define %residual-fx<=? (cmp-reducer fx<=?))
(define %residual-fx>=? (cmp-reducer fx>=?))
(define %residual-fl=? (cmp-reducer fl=?))
(define %residual-fl<? (cmp-reducer fl<?))
(define %residual-fl>? (cmp-reducer fl>?))
(define %residual-fl<=? (cmp-reducer fl<=?))
(define %residual-fl>=? (cmp-reducer fl>=?))
(define %residual= (cmp-reducer =))  
(define %residual< (cmp-reducer <))
(define %residual> (cmp-reducer >))
(define %residual<= (cmp-reducer <=))
(define %residual>= (cmp-reducer >=))

(define-syntax minmax-reducer
  (syntax-rules ()
    [(_ f)
     (lambda (x . args)
       (let loop ([x x] [args args])
         (if (null? args)
             x
             (loop (f x (car args)) (cdr args)))))]))

(define %residual-fxmax (minmax-reducer fxmax))
(define %residual-fxmin (minmax-reducer fxmin))
(define %residual-flmax (minmax-reducer flmax))
(define %residual-flmin (minmax-reducer flmin))

(define (%residual-max/2 a b)
  (if (fixnum? a)
      (if (fixnum? b)
          (if (fx>? a b) a b)
          (let ([a (fixnum->flonum a)]) (if (fl>? a b) a b)))
      (if (fixnum? b)
          (let ([b (fixnum->flonum b)]) (if (fl>? a b) a b))
          (if (fl>? a b) a b))))
(define %residual-max (minmax-reducer %residual-max/2))

(define (%residual-min/2 a b)
  (if (fixnum? a)
      (if (fixnum? b)
          (if (fx<? a b) a b)
          (let ([a (fixnum->flonum a)]) (if (fl<? a b) a b)))
      (if (fixnum? b)
          (let ([b (fixnum->flonum b)]) (if (fl<? a b) a b))
          (if (fl<? a b) a b))))
(define %residual-min (minmax-reducer %residual-min/2))
  
(define-syntax addmul-reducer
  (syntax-rules ()
    [(_ f s)
     (lambda args
       (if (null? args)
           s
           (let loop ([x (car args)] [args (cdr args)])
             (if (null? args)
                 x
                 (loop (f x (car args)) (cdr args))))))]))

(define %residual-fx+ (addmul-reducer fx+ 0))
(define %residual-fx* (addmul-reducer fx* 1))
(define %residual-fl+ (addmul-reducer fl+ 0.0))
(define %residual-fl* (addmul-reducer fl* 1.0))
(define %residual+ (addmul-reducer + 0))
(define %residual* (addmul-reducer * 1))
(define %residual-gcd (addmul-reducer gcd 0))
(define %residual-lcm (addmul-reducer lcm 1))

(define-syntax subdiv-reducer
  (syntax-rules ()
    [(_ f)
     (lambda (x . args)
       (if (null? args)
           (f x)
           (let loop ([x x] [args args])
             (if (null? args)
                 x
                 (loop (f x (car args)) (cdr args))))))]))

(define %residual-fx- (subdiv-reducer fx-))
(define %residual-fx/ (subdiv-reducer fx/))
(define %residual-fl- (subdiv-reducer fl-))
(define %residual-fl/ (subdiv-reducer fl/))
(define %residual- (subdiv-reducer -))
(define %residual/ (subdiv-reducer /))

(define-syntax nullary-unary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda args
       (if (null? args) (f) (f (car args))))]))

(define-syntax nullary-unary-binary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda args
       (if (null? args) (f) (if (null? (cdr args)) (f (car args)) (f (car args) (cadr args)))))])) 

(define-syntax unary-binary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda (x . args)
       (if (null? args) (f x) (f x (car args))))]))

(define-syntax unary-binary-ternary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda (x . args)
       (if (null? args) (f x) (if (null? (cdr args)) (f x (car args)) (f x (car args) (cadr args)))))])) 

(define-syntax unary-binary-ternary-quaternary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda (x . args)
       (if (null? args) (f x) (if (null? (cdr args)) (f x (car args)) 
         (if (null? (cddr args)) (f x (car args) (cadr args)) (f x (car args) (cadr args) (caddr args))))))])) 

(define-syntax binary-ternary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda (x y . args)
       (if (null? args) (f x y) (f x y (car args))))]))

(define-syntax binary-ternary-quaternary-adaptor
  (syntax-rules ()
    [(_ f)
     (lambda (x y . args)
       (if (null? args) (f x y) 
           (if (null? (cdr args)) (f x y (car args)) (f x y (car args) (cadr args)))))]))

(define %residual-log (unary-binary-adaptor log))

(define %residual-flatan (unary-binary-adaptor flatan))
(define %residual-atan (unary-binary-adaptor atan))

(define %residual-member (binary-ternary-adaptor member)) 
(define %residual-assoc (binary-ternary-adaptor assoc)) 

(define (%residual-map p l . l*)
  (if (null? l*) 
      (let loop ([l l] [r '()])
        (if (pair? l) (loop (cdr l) (cons (p (car l)) r)) (reverse! r)))
      (let loop ([l* (cons l l*)] [r '()])
        (if (let lp ([l* l*]) (or (null? l*) (and (pair? (car l*)) (lp (cdr l*)))))
            (loop (map cdr l*) (cons (apply p (map car l*)) r))
            (reverse! r)))))

(define (%residual-for-each p l . l*)
  (if (null? l*) 
      (let loop ([l l]) (if (pair? l) (begin (p (car l)) (loop (cdr l)))))
      (let loop ([l* (cons l l*)])
        (if (let lp ([l* l*]) (or (null? l*) (and (pair? (car l*)) (lp (cdr l*)))))
            (begin (apply p (map car l*)) (loop (map cdr l*)))))))

(define (string-map p s . s*)
  (if (null? s*)
      (let* ([len (string-length s)] [res (make-string len)])
        (do ([i 0 (fx+ i 1)]) [(fx>=? i len) res]
           (string-set! res i (p (string-ref s i)))))
      (list->string (apply map p (map string->list (cons s s*))))))

(define (vector-map p v . v*)
  (if (null? v*)
      (let* ([len (vector-length v)] [res (make-vector len)])
        (do ([i 0 (fx+ i 1)]) [(fx>=? i len) res]
          (vector-set! res i (p (vector-ref v i)))))
      (list->vector (apply map p (map vector->list (cons v v*))))))

(define (string-for-each p s . s*)
  (if (null? s*) 
      (let ([len (string-length s)])
        (do ([i 0 (fx+ i 1)]) [(fx>=? i len)] (p (string-ref s i))))
      (apply for-each p (map string->list (cons s s*)))))

(define (vector-for-each p v . v*)
  (if (null? v*)
      (let ([len (vector-length v)])
        (do ([i 0 (fx+ i 1)]) [(fx>=? i len)] (p (vector-ref v i))))
      (apply for-each p (map vector->list (cons v v*)))))

(define-syntax append-reducer
  (syntax-rules ()
    [(_ f s)
     (lambda args
       (let loop ([args args])
         (cond [(null? args) s]
               [(null? (cdr args)) (car args)]
               [else (f (car args) (loop (cdr args)))])))]))

(define %residual-char=? (cmp-reducer char=?))
(define %residual-char<? (cmp-reducer char<?))
(define %residual-char>? (cmp-reducer char>?))
(define %residual-char<=? (cmp-reducer char<=?))
(define %residual-char>=? (cmp-reducer char>=?))
(define %residual-char-ci=? (cmp-reducer char-ci=?))
(define %residual-char-ci<? (cmp-reducer char-ci<?))
(define %residual-char-ci>? (cmp-reducer char-ci>?))
(define %residual-char-ci<=? (cmp-reducer char-ci<=?))
(define %residual-char-ci>=? (cmp-reducer char-ci>=?))

(define %residual-make-string (unary-binary-adaptor make-string))

(define (%residual-string . l) 
  (list->string l))

(define %residual-string-append (append-reducer string-append ""))

(define %residual-string=? (cmp-reducer string=?))
(define %residual-string<? (cmp-reducer string<?))
(define %residual-string>? (cmp-reducer string>?))
(define %residual-string<=? (cmp-reducer string<=?))
(define %residual-string>=? (cmp-reducer string>=?))
(define %residual-string-ci=? (cmp-reducer string-ci=?))
(define %residual-string-ci<? (cmp-reducer string-ci<?))
(define %residual-string-ci>? (cmp-reducer string-ci>?))
(define %residual-string-ci<=? (cmp-reducer string-ci<=?))
(define %residual-string-ci>=? (cmp-reducer string-ci>=?))

(define %residual-make-vector (unary-binary-adaptor make-vector))

(define (%residual-vector . l) 
  (list->vector l))

(define %residual-make-bytevector (unary-binary-adaptor make-bytevector))

(define (%residual-bytevector . l) 
  (list->bytevector l))

(define (%residual-list . l) l)

(define %residual-make-list (unary-binary-adaptor make-list))

(define (%residual-cons* x . l)
  (let loop ([x x] [l l])
    (if (null? l) x (cons x (loop (car l) (cdr l))))))

(define %residual-append (append-reducer append '()))

(define %residual-record? (unary-binary-adaptor record?))

(define %residual-number->string (unary-binary-adaptor number->string))
(define %residual-string->number (unary-binary-adaptor string->number))

(define %residual-symbol=? (cmp-reducer symbol=?))  

(define (%fail-lambda . args)
  (error 'case-lambda "unexpected number of arguments" args))

(define (%residual-make-case-lambda . l)
  (%prim* "{ /* %residual-make-case-lambda */
    obj l; int i, c = fixnum_from_$arg;
    hreserve(hbsz(c+1), $live); /* $live live regs */
    l = obj_from_$arg; /* gc-safe */
    for (i = 0; i < c; ++i, l = cdr(l)) hp[i-c] = car(l);
    hp -= c; *--hp = obj_from_objptr(appcases+4);
    $return obj(hendblk(c+1)); }" (length l) l))

(define %residual-current-input-port (nullary-unary-binary-adaptor current-input-port))
(define %residual-current-output-port (nullary-unary-binary-adaptor current-output-port))
(define %residual-current-error-port (nullary-unary-binary-adaptor current-error-port))

(define %residual-read-char (nullary-unary-adaptor read-char))
(define %residual-peek-char (nullary-unary-adaptor peek-char))
(define %residual-char-ready? (nullary-unary-adaptor char-ready?))
(define %residual-read-line (nullary-unary-adaptor read-line))

(define %residual-display-fixnum (unary-binary-adaptor display-fixnum))
(define %residual-display-flonum (unary-binary-adaptor display-flonum))
(define %residual-display-procedure (unary-binary-adaptor display-procedure))
(define %residual-display-input-port (unary-binary-adaptor display-input-port))
(define %residual-display-output-port (unary-binary-adaptor display-output-port))

(define %residual-write-char (unary-binary-adaptor write-char))
(define %residual-write-string (unary-binary-ternary-quaternary-adaptor write-string))
(define %residual-newline (nullary-unary-adaptor newline))
(define %residual-flush-output-port (nullary-unary-adaptor flush-output-port))

(define %residual-read-u8 (nullary-unary-adaptor read-u8))
(define %residual-peek-u8 (nullary-unary-adaptor peek-u8))
(define %residual-u8-ready? (nullary-unary-adaptor u8-ready?))
(define %residual-write-u8 (unary-binary-adaptor write-u8))
(define %residual-write-bytevector (unary-binary-ternary-quaternary-adaptor write-bytevector))

(define %residual-write-simple (unary-binary-adaptor write-simple))
(define %residual-write-shared (unary-binary-adaptor write-shared))
(define %residual-write (unary-binary-adaptor write))
(define %residual-display (unary-binary-adaptor display))

(define %residual-read (nullary-unary-adaptor read))
(define %residual-read-simple (nullary-unary-adaptor read-simple))

(define %residual-exit (nullary-unary-adaptor exit))