Register reassignment

examples/hello.modal

@@ -1,4 +1,5 @@
 <> (?x dup) (?x ?x)
 <> (?x ?y swap) (?y ?x)
+<> ( ?x pop) ()
 
-(A B swap) dup
+(1 2 3) (4 5 6) swap pop dup

examples/test.modal

@@ -1,5 +1,4 @@
-<> (?x dup) (?x ?x)
-<> (?x ?y swap) (?y ?x)
-<> ( ?x pop) ()
+<> (eq ?x ?x) (#t)
+<> (eq ?x ?y) (#f)
 
-(1 2 3) (4 5 6) swap pop dup
+(eq fox fox) (eq fox owl)

makefile

@@ -1,7 +1,7 @@
 RELEASE_flags=-DNDEBUG -O2 -g0 -s
 DEBUG_flags=-std=c89 -D_POSIX_C_SOURCE=199309L -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined
 
-.PHONY: all debug dest run test install uninstall format clean
+.PHONY: all debug dest run test install uninstall format clean archive
 
 all: dest bin/modal
 
@@ -13,13 +13,15 @@ test: all
 	@ bin/modal -v 
 	@ bin/modal examples/test.modal
 install: all 
-	@ cp bin/modal ~/bin/
+	cp bin/modal ~/bin/
 uninstall:
-	@ rm -f ~/bin/modal
+	rm -f ~/bin/modal
 format:
 	@ clang-format -i src/modal.c
 clean:
-	@ rm -fr bin
+	rm -fr bin
+archive: all
+	cp src/modal.c ../oscean/etc/modal.c.txt
 
 bin/modal: src/modal.c
 	@ cc ${DEBUG_flags} ${CFLAGS} src/modal.c -o bin/modal

src/modal.c

@@ -30,12 +30,33 @@ walk(char *s)
 	return s;
 }
 
+static int
+compare(char *a, char *b)
+{
+	int i = 0, al = walk(a) - a, bl = walk(b) - b;
+	if(al != bl) return 0;
+	while(a[i] == b[i])
+		if(!a[i] || ++i >= al) return 1;
+	return 0;
+}
+
 static char *
 match(char *p, Rule *r)
 {
+	int i;
 	char c, *a = r->a, *b = p;
+	for(i = 0x21; i < 0x7f; i++)
+		regs[i] = 0;
 	while((c = *a)) {
-		if(c == '?') regs[(int)*(++a)] = b, a++, b = walk(b), c = *b;
+		if(c == '?') {
+			int id = (int)*(++a);
+			if(regs[id]) {
+				if(!compare(regs[id], b))
+					return NULL;
+			} else
+				regs[id] = b;
+			a++, b = walk(b), c = *b;
+		}
 		if(!a[0]) return b;
 		if(c != *b) return NULL;
 		a++, b++;
@@ -68,7 +89,7 @@ save(int rule)
 	/* todo: change pointer instead of copying memory */
 	for(i = 0; i <= end; i++) prog[i] = outp[i];
 	prog_ = prog, outp_ = outp;
-	printf("..%02d %s\n", rule, prog);
+	printf("%02d %s\n", rule, prog);
 }
 
 static int
@@ -107,7 +128,7 @@ print_rules(void)
 {
 	int i;
 	for(i = 0; i < rules_len; i++)
-		printf("Rule #%d: <%s> -> <%s>\n", i, rules[i].a, rules[i].b);
+		printf("<> (%s) (%s)\n", rules[i].a, rules[i].b);
 	printf("\n");
 }
 
@@ -180,10 +201,10 @@ main(int argc, char **argv)
 	if(argc < 2)
 		return !printf("usage: modal [-v] source.modal\n");
 	if(argc < 3 && argv[1][0] == '-' && argv[1][1] == 'v')
-		return !printf("Modal - Modal Interpreter, 3 Apr 2024.\n");
+		return !printf("Modal - Modal Interpreter, 4 Apr 2024.\n");
 	parse(argv[1]);
 	print_rules();
-	printf(".... %s\n", prog);
+	printf(".. %s\n", prog);
 	while(rewrite())
 		;
 	return 0;