parameters, errors, exceptions, guard

This commit is contained in:
ESL 2023-03-30 16:09:25 -04:00
parent 623455a8e3
commit 74c3b9ffef
4 changed files with 334 additions and 11 deletions

16
i.c
View file

@ -573,6 +573,22 @@ define_instruction(panic) {
unwindi(0);
}
define_instruction(abort) {
/* exit code ignored */
abort();
unwindi(0);
}
define_instruction(exit) {
int excode;
if (ac == bool_obj(0)) excode = 1;
else if (ac == bool_obj(1)) excode = 0;
else if (is_fixnum(ac)) excode = (int)get_fixnum(ac);
else excode = 1;
exit(excode);
unwindi(0);
}
define_instruction(lit) {
ac = *ip++;

2
i.h
View file

@ -513,6 +513,8 @@ declare_instruction(clock, "Z3", 0, "current-jiffy",
declare_instruction(clops, "Z4", 0, "jiffies-per-second", '0', AUTOGL)
declare_instruction(cursec, "Z5", 0, "current-second", '0', AUTOGL)
declare_instruction(panic, "Z7", 0, "%panic", '2', AUTOGL)
declare_instruction(abort, "Z8\0t", 0, "%abort", 'u', AUTOGL)
declare_instruction(exit, "Z9\0t", 0, "%exit", 'u', AUTOGL)
/* serialization and deserialization instructions */
declare_instruction(igp, "U0", 0, "integrable?", '1', AUTOGL)

136
s.c
View file

@ -171,6 +171,27 @@ char *s_code[] = {
"l3:y12:syntax-rules;n;l2:l2:y1:_;y1:x;;l2:y11:delay-force;l2:y12:make-"
"promise;y1:x;;;;",
"C", 0,
"&0{%2${.2,.4[01},#0.2,.1,&2{%2.1?{.0:!0]2}.0,:1[21}%x,.3,.2,&2{%1${.2,"
":1[01}:!0]1}%x,.2,&1{%0:0^]0}%x,&3{|00|11|22%%}]3}%x,&0{%1#0.0,&1{%2.1"
"?{.0:!0]2}.0]2}%x,.1,&1{%1.0:!0]1}%x,.2,&1{%0:0^]0}%x,&3{|00|11|22%%}]"
"1}%x,&2{|10|21%%}@!(y14:make-parameter)",
"S", "%parameterize-loop",
"l4:y12:syntax-rules;n;l2:l4:y1:_;l2:l5:y5:param;y5:value;y1:p;y3:old;y"
"3:new;;y3:...;;n;y4:body;;l3:y3:let;l2:l2:y1:p;y5:param;;y3:...;;l3:y3"
":let;l4:l2:y3:old;l1:y1:p;;;y3:...;l2:y3:new;l3:y1:p;y5:value;f;;;y3:."
"..;;l4:y12:dynamic-wind;l4:y6:lambda;n;l3:y1:p;y3:new;t;;y3:...;;py6:l"
"ambda;pn;y4:body;;;l4:y6:lambda;n;l3:y1:p;y3:old;t;;y3:...;;;;;;l2:l4:"
"y1:_;y4:args;pl2:y5:param;y5:value;;y4:rest;;y4:body;;l4:y18:%25parame"
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"dy;;;l4:y18:%25parameterize-loop;n;l2:l2:y5:param;y5:value;;y3:...;;y4"
":body;;;",
"P", "new-record-type",
"%2.1,.1c]2",
@ -581,11 +602,122 @@ char *s_code[] = {
"I+,:3^[11}.!0.0^_1[41}${.2,.5c,@(y13:%25vector->list),@(y5:%25map1)[02"
"},.2c,@(y9:%25for-each),@(y13:apply-to-list)[32",
"P", "abort",
"%0tZ8]0",
"P", "reset",
"%0'1Z9]0",
"P", "set-reset-handler!",
"%1.0@!(y5:reset)]1",
"P", "print-error-message",
"%3,,,#0#1#2.1,&1{%2.0p?{.0a~?{${.3,'(s2:: ),@(y12:write-string)[02}.1,"
".1d,:0^[22}.0aY0?{${.3,'(s4: in ),@(y12:write-string)[02}.1,.1aW5${.3,"
"'(s2:: ),@(y12:write-string)[02}.1,.1d,:0^[22}${.3,'(s2:: ),@(y12:writ"
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"}.!2.3S0,.0?{.0}{.4Y0}_1?{${.7,.6,@(y12:write-string)[02}}{${.7,'(s5:E"
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"C", 0,
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"P", "error-object",
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"P", "error-object?",
"%1@(y14:<error-object>),.1O0]1",
"P", "error-object-kind",
"%1'0,.1O4]1",
"P", "error-object-message",
"%1'1,.1O4]1",
"P", "error-object-irritants",
"%1'2,.1O4]1",
"P", "error",
"%!1.0,.2Z7]2",
"%!1${.2,.4,f,@(y12:error-object)[03},@(y5:raise)[21",
"C", 0,
"${,#0&0{%1${.2,@(y13:error-object?)[01}?{${.2,@(y22:error-object-irrit"
"ants)[01},${.3,@(y20:error-object-message)[01}c,${.3,@(y17:error-objec"
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")",
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"0},.0,.3,&2{%0t,:1,:0[02},.6,&1{%0:0[00},.3,.5,&2{%0t,:1,:0[02},@(y12:"
"dynamic-wind)[63",
"P", "raise",
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"2:y4:temp;y4:test;;;l4:y2:if;y4:temp;l2:y6:result;y4:temp;;y7:reraise;"
";;;l2:l6:y1:_;y7:reraise;l3:y4:test;y2:=>;y6:result;;y7:clause1;y7:cla"
"use2;y3:...;;l3:y3:let;l1:l2:y4:temp;y4:test;;;l4:y2:if;y4:temp;l2:y6:"
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"3:...;;;;;l2:l3:y1:_;y7:reraise;l1:y4:test;;;l3:y2:or;y4:test;y7:rerai"
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";l4:y2:if;y4:test;l4:y5:begin;y7:result1;y7:result2;y3:...;;l5:y10:%25"
"guard-aux;y7:reraise;y7:clause1;y7:clause2;y3:...;;;;",
"S", "guard",
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";y2:e2;y3:...;;l1:l2:y7:call/cc;l3:y6:lambda;l1:y7:guard-k;;l3:y22:wit"
"h-exception-handler;l3:y6:lambda;l1:y9:condition;;l1:l2:y7:call/cc;l3:"
"y6:lambda;l1:y9:handler-k;;l2:y7:guard-k;l3:y6:lambda;n;l3:y3:let;l1:l"
"2:y3:var;y9:condition;;;l4:y10:%25guard-aux;l2:y9:handler-k;l3:y6:lamb"
"da;n;l2:y17:raise-continuable;y9:condition;;;;y6:clause;y3:...;;;;;;;;"
";l3:y6:lambda;n;l3:y16:call-with-values;l5:y6:lambda;n;y2:e1;y2:e2;y3:"
"...;;l3:y6:lambda;y4:args;l2:y7:guard-k;l3:y6:lambda;n;l3:y5:apply;y6:"
"values;y4:args;;;;;;;;;;;;",
"P", "read-error",
"%!1.0,.2Z7]2",
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"P", "file-error",
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"nd)[01}q]1}f]1",
"P", "port?",
"%1.0P00,.0?{.0]2}.1P01]2",

191
src/s.scm
View file

@ -222,6 +222,42 @@
(syntax-rules () [(_ x) (delay-force (make-promise x))]))
;---------------------------------------------------------------------------------------------
; Dynamic bindings
;---------------------------------------------------------------------------------------------
(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-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)
(%parameterize-loop ([param value p old new] . args) rest body)]))
(define-syntax parameterize
(syntax-rules ()
[(_ ([param value] ...) . body)
(%parameterize-loop () ([param value] ...) body)]))
;---------------------------------------------------------------------------------------------
; Record type definitions
;---------------------------------------------------------------------------------------------
@ -1144,20 +1180,157 @@
;TBD:
;
;with-exception-handler
;raise
;raise-continuable
;error-object?
;error-object-message
;error-object-irritants
; (with-exception-handler handler thunk)
; (raise obj)
; (raise-continuable obj)
; (error-object? x)
; (error-object-message e)
; (error-object-irritants e)
;read-error?
;file-error?
(define (error msg . args)
(%panic msg args)) ; should work for now
(define (abort) (%abort))
(define (reset) (%exit 1))
(define (set-reset-handler! fn) (set! reset fn))
(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)
(%exit 1)))
(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-syntax %guard-aux
(syntax-rules (else =>)
[(_ reraise (else result1 result2 ...))
(begin result1 result2 ...)]
[(_ reraise (test => result))
(let ([temp test]) (if temp (result temp) reraise))]
[(_ reraise (test => result) clause1 clause2 ...)
(let ([temp test])
(if temp
(result temp)
(%guard-aux reraise clause1 clause2 ...)))]
[(_ reraise (test)) (or test reraise)]
[(_ reraise (test) clause1 clause2 ...)
(let ([temp test])
(if temp temp (%guard-aux reraise clause1 clause2 ...)))]
[(_ reraise (test result1 result2 ...))
(if test (begin result1 result2 ...) reraise)]
[(_ reraise (test result1 result2 ...) clause1 clause2 ...)
(if test
(begin result1 result2 ...)
(%guard-aux reraise clause1 clause2 ...))]))
(define-syntax guard
(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)
(%panic msg args)) ; should work for now
(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)))
;---------------------------------------------------------------------------------------------