From c174832c8ef6af6f738481c2ed479d338f8fe46d Mon Sep 17 00:00:00 2001
From: Devine Lu Linvega <aliceffekt@gmail.com>
Date: Thu, 4 Apr 2024 14:55:51 -0700
Subject: [PATCH] Skip empty rules

---
 src/modal.c | 34 ++++++++++++++++++----------------
 test.modal  |  2 +-
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/modal.c b/src/modal.c
index ee4ab26..47b6088 100644
--- a/src/modal.c
+++ b/src/modal.c
@@ -53,11 +53,22 @@ writereg(char r)
 	return 1;
 }
 
+static void
+save(void)
+{
+	int i, end = outp_ - outp;
+	for(i = 0; i < end; i++)
+		prog[i] = outp[i];
+	prog[i] = 0;
+	prog_ = prog;
+	outp_ = outp;
+	printf(".. %s\n", prog);
+}
+
 static int
 rewrite(void)
 {
 	char c, *p = prog;
-	printf("STEP ---------\n");
 	while((c = *p)) {
 		int i, found = 0;
 		for(i = 0; i < rules_len; i++) {
@@ -65,7 +76,6 @@ rewrite(void)
 			char *res = match(p, r);
 			if(res != NULL) {
 				char cc, *b = r->b;
-				printf("MATCH: %s -> %s\n", r->a, r->b);
 				while((cc = *b++)) {
 					if(cc == '?')
 						writereg(*b++);
@@ -82,18 +92,19 @@ rewrite(void)
 		}
 	}
 	*outp_++ = 0;
+	save();
 	return 1;
 }
 
 static void
-display(void)
+print_rules(void)
 {
 	int i;
 	for(i = 0; i < rules_len; i++) {
 		Rule *r = &rules[i];
 		printf("Rule #%d: %s -> %s\n", i, r->a, r->b);
 	}
-	printf("\nStep %s -- %s\n", prog, outp);
+	printf("\n");
 }
 
 static char *
@@ -117,6 +128,7 @@ static void
 tokenize(char *t, FILE *f)
 {
 	char c;
+	if(!t[0]) return;
 	if(t[0] == '<' && t[1] == '>') {
 		Rule *r = &rules[rules_len++];
 		r->a = parse_rulefrag(f), r->b = parse_rulefrag(f);
@@ -147,15 +159,6 @@ parse(char *path)
 	return 1;
 }
 
-static void
-save(void)
-{
-	int i, end = outp_ - outp;
-	for(i = 0; i < end; i++)
-		prog[i] = outp[i];
-	prog[i] = 0;
-}
-
 int
 main(int argc, char **argv)
 {
@@ -164,10 +167,9 @@ main(int argc, char **argv)
 	if(argc < 3 && argv[1][0] == '-' && argv[1][1] == 'v')
 		return !printf("Modal - Modal Interpreter, 3 Apr 2024.\n");
 	parse(argv[1]);
+	print_rules();
+	printf(".. %s\n", prog);
 	rewrite();
-	display();
-	save();
 	rewrite();
-	display();
 	return 0;
 }
\ No newline at end of file
diff --git a/test.modal b/test.modal
index 0c2e849..dd63d61 100644
--- a/test.modal
+++ b/test.modal
@@ -1,4 +1,4 @@
-<> (?x ?y swap) (?y ?x)
 <> (?x dup) (?x ?x)
+<> (?x ?y swap) (?y ?x)
 
 foo ((A B swap) dup)
\ No newline at end of file