predicate words experiment

src/main/java/com/vectron/fcl/Dictionary.java

@@ -9,8 +9,10 @@ import java.util.Set;
 
 public class Dictionary {
     private final List<Word> dict = new ArrayList<>();
+    private final Fcl fcl;
 
-    public Dictionary() {
+    public Dictionary(Fcl fcl) {
+        this.fcl = fcl;
     }
 
     public void add(Word word) {
@@ -20,7 +22,7 @@ public class Dictionary {
     public Word at(String name) {
         for (int i = dict.size() - 1; i >= 0; i--) {
             Word each = dict.get(i);
-            if (each.visible() && name.equals(each.name()))
+            if (each.match(name, fcl))
                 return each;
         }
         return null;

src/main/java/com/vectron/fcl/Fcl.java

@@ -29,7 +29,7 @@ public class Fcl {
     private static final String EXIT = "exit";
     private final int SCRATCH_SIZE = 1024;
     private enum Mode { COMPILE, INTERPRET }
-    private final Dictionary dict = new Dictionary();
+    private final Dictionary dict;
     private final FclStack rstack = new FclStack();
     private final JvmInterOp interOp;
     private final FclStack stack;
@@ -47,6 +47,7 @@ public class Fcl {
         private final String name;
         private boolean visible = true;
         private boolean immediate = false;
+        private Word predicate;
 
         public ColonDef(int address, String name) {
             this.address = address;
@@ -70,11 +71,6 @@ public class Fcl {
             this.visible = isVisible;
         }
 
-        @Override
-        public boolean visible() {
-            return visible;
-        }
-
         @Override
         public boolean immediate() {
             return immediate;
@@ -85,6 +81,26 @@ public class Fcl {
             immediate = isImmediate;
         }
 
+        @Override
+        public void predicate(Word word) {
+            this.predicate = word;
+        }
+
+        @Override
+        public boolean match(String name, Fcl fcl) {
+            return visible && (this.name.equals(name) || predicateMatch(name, fcl));
+        }
+
+        private boolean predicateMatch(String name, Fcl fcl) {
+            if (predicate == null) return false;
+            fcl.push(new Str(name));
+            predicate.enter();
+            boolean match = fcl.pop().boolValue();
+            if (match)
+                fcl.push(new Str(name));
+            return match;
+        }
+
         @Override
         public String toString() {
             return "xt_" + name + " (" + address + ")";
@@ -155,11 +171,6 @@ public class Fcl {
             this.visible = isVisible;
         }
 
-        @Override
-        public boolean visible() {
-            return visible;
-        }
-
         @Override
         public boolean immediate() {
             return false;
@@ -170,6 +181,16 @@ public class Fcl {
             throw new Aborted("Cannot make immediate val");
         }
 
+        @Override
+        public void predicate(Word word) {
+            throw new Aborted("var does not support predicate");
+        }
+
+        @Override
+        public boolean match(String name, Fcl fcl) {
+            return visible && this.name.equals(name);
+        }
+
         @Override
         public void enter() {
             stack.push(new Num(address));
@@ -249,11 +270,6 @@ public class Fcl {
             this.visible = isVisible;
         }
 
-        @Override
-        public boolean visible() {
-            return visible;
-        }
-
         @Override
         public boolean immediate() {
             return false;
@@ -264,6 +280,16 @@ public class Fcl {
             throw new Aborted("Cannot make immediate val");
         }
 
+        @Override
+        public void predicate(Word word) {
+            throw new Aborted("val does not support predicate");
+        }
+
+        @Override
+        public boolean match(String name, Fcl fcl) {
+            return visible && this.name.equals(name);
+        }
+
         @Override
         public void enter() {
             stack.push(value);
@@ -329,6 +355,7 @@ public class Fcl {
     }
 
     public Fcl(FclStack stack, int heapSize, Transcript transcript) {
+        this.dict = new Dictionary(this);
         this.stack = stack;
         this.heap = new Object[heapSize];
         this.interOp = new JvmInterOp(stack);
@@ -386,6 +413,7 @@ public class Fcl {
         addPrimitive("here", () -> stack.push(new Num(dp)));
         addPrimitive("dp!", () -> dp = stack.pop().intValue() );
         addPrimitive("interpret", () -> mode = Mode.INTERPRET);
+        addPrimitive("interpret?", () -> stack.push(mode == Mode.INTERPRET ? Bool.TRUE : Bool.FALSE));
         addPrimitive("trace", () -> trace = stack.pop().boolValue());
         addPrimitive("lit", () -> stack.push((Obj)heap[ip++]));
         addPrimitive(">r", () -> rstack.push(stack.pop()));
@@ -398,6 +426,8 @@ public class Fcl {
         addPrimitive("[']", () -> stack.push((Word)heap[ip++]));
         addPrimitive("`", () -> { Word word = dict.at(word()); stack.push(word == null ? Nil.INSTANCE : word); });
         addPrimitive("immediate", () -> dict.lastWord().immediate(true), true);
+        addPrimitive("lastword", () -> stack.push(dict.lastWord()));
+        addPrimitive("set-predicate", () -> ((Word)stack.pop()).predicate((Word)stack.pop()));
         addPrimitive(".", () -> show(stack.pop()));
         addPrimitive("jvm-call-static", interOp::jvmCallStatic);
         addPrimitive("jvm-call-method", interOp::jvmCallMethod);
@@ -657,6 +687,10 @@ public class Fcl {
         return stack.pop();
     }
 
+    public void push(Obj obj) {
+        stack.push(obj);
+    }
+
     public int stackSize() {
         return stack.size();
     }

src/main/java/com/vectron/fcl/types/Primitive.java

@@ -1,5 +1,7 @@
 package com.vectron.fcl.types;
 
+import com.vectron.fcl.Fcl;
+import com.vectron.fcl.exceptions.Aborted;
 import com.vectron.fcl.exceptions.TypeMismatched;
 
 import static com.vectron.fcl.Fcl.STRICT;
@@ -21,13 +23,18 @@ public class Primitive implements Word {
     }
 
     @Override
-    public boolean visible() {
+    public boolean immediate() {
-        return visible;
+        return immediate;
     }
 
     @Override
-    public boolean immediate() {
+    public void predicate(Word word) {
-        return immediate;
+        throw new Aborted("primitive does not support predicate");
+    }
+
+    @Override
+    public boolean match(String name, Fcl fcl) {
+        return visible && this.name.equals(name);
     }
 
     @Override

src/main/java/com/vectron/fcl/types/Word.java

@@ -1,10 +1,13 @@
 package com.vectron.fcl.types;
 
+import com.vectron.fcl.Fcl;
+
 public interface Word extends Obj {
     void enter();
     String name();
     void visible(boolean isVisible);
-    boolean visible();
     boolean immediate();
     void immediate(boolean isImmediate);
+    void predicate(Word word);
+    boolean match(String name, Fcl fcl);
 }

src/main/res/raw/misc.forth

@@ -13,7 +13,8 @@
     } each
     tbl ;
 
-: ms ( n -- ) 'java.lang.Thread/sleep/l' jvm-call-static ;
+: ms ( n -- ) :java.lang.Thread/sleep/l jvm-call-static ;
-
 : tone ( hz ms -- ) swap :com.vectron.forthcalc.support.Tone/play/di jvm-call-static ;
 : torch ( n -- ) :com.vectron.forthcalc.support.Torch/toggle/O jvm-call-static ;
+
+: match: immediate ` lastword set-predicate ;

src/main/res/raw/plot.forth

@@ -81,9 +81,10 @@ var: oy
     2 LINE-COLOR paint
     nil => px nil => py 1 => x
     ls { -> y
-        x @ y trans 5 draw-circle
         px @ nil != if
             px @ py @ trans x @ y trans draw-line
+            x @ y trans 3 draw-circle
+            \ 0 x @ y trans 20 + y >str draw-text
         then
         x @ px ! y py !
         x inc

src/test/java/com/vectron/fcl/FclTest.java

@@ -1236,6 +1236,16 @@ public class FclTest {
         assertEquals(true, evalPop(": tst :my-symbol :my-symbol = ; tst").boolValue());
     }
 
+    @Test
+    public void testPredicateWords() {
+        eval(": octal? ( token -- ) 0 at '&' = ;\n" +
+                ": lit-oct ( token -- n ) immediate match: octal?\n" +
+                "   1 over size substr 8 swap :java.lang.Long/parseLong/si jvm-call-static\n" +
+                "   interpret? not if ['] lit , , then ;\n");
+        assertEquals(177, evalPop("&261").intValue());
+        assertEquals(169, evalPop(": tst &261 &10 - ; tst ").intValue());
+    }
+
     private String transcript() {
         return transcript.content();
     }