Break out of compilation early

src/modal.c

@@ -162,15 +162,21 @@ static char *
 compile_rule(Rule *r, int id, char *src)
 {
 	int wrapped, reg;
-	char c, *cap, *s, *s2;
+	char c, *cap, *s2;
 	r->id = id, r->ptr = 0;
 
 	/* left ==================================== */
 
 	r->a = dict_;
 	s2 = src;
+
 	while((c = *s2) && c == ' ') s2++;
-	if(c != ')' && !(c == '<' && s2[1] == '>')) {
+	if(c == ')' || (c == '<' && s2[1] == '>')) {
+		r->b = dict_;
+		*dict_++ = 0;
+		return s2;
+	}
+
 	cap = walk(s2);
 	wrapped = c == '(';
 	if(wrapped) s2++, cap--;
@@ -185,7 +191,7 @@ compile_rule(Rule *r, int id, char *src)
 			*dict_++ = *s2++;
 	}
 	s2 += wrapped;
-	}
+
 	*dict_++ = 0;
 	src = s2;
 
@@ -193,23 +199,30 @@ compile_rule(Rule *r, int id, char *src)
 
 	r->b = dict_;
 	s2 = src;
+
 	while((c = *s2) && c == ' ') s2++;
-	if(c != ')' && !(c == '<' && s2[1] == '>')) {
+	if(c == ')' || (c == '<' && s2[1] == '>')) {
+		*dict_++ = 0;
+		return s2;
+	}
+
 	cap = walk(s2);
 	wrapped = c == '(';
 	if(wrapped) s2++, cap--;
-		while(s2 < cap) *dict_++ = *s2++;
+	while(s2 < cap) {
-		s2 += wrapped;
+		*dict_++ = *s2++;
 	}
+	s2 += wrapped;
+
 	*dict_++ = 0;
 	src = s2;
 
-	s = r->b;
+	s2 = r->b;
-	while((c = *s++)) { /* right */
+	while((c = *s2++)) { /* right */
 		if(c == '?') {
-			reg = find_register(r, *s);
+			reg = find_register(r, *s2);
 			if(reg >= 0)
-				*s = '0' + reg;
+				*s2 = '0' + reg;
 		}
 	}
 	return src;