diff --git a/src/modal.c b/src/modal.c
index 571d8ec..32c3843 100644
--- a/src/modal.c
+++ b/src/modal.c
@@ -176,11 +176,13 @@ find_register(Rule *r, char reg)
 	return -1;
 }
 
-static void
-compile_rule(Rule *r)
+static char *
+compile_rule(Rule *r, char *src)
 {
 	int i;
 	char c, *s;
+	r->a = dict_, src = parse_frag(src);
+	r->b = dict_, src = parse_frag(src);
 	r->ptr = 0;
 	s = r->a;
 	while((c = *s++)) { /* left */
@@ -199,6 +201,7 @@ compile_rule(Rule *r)
 				*s = '0' + reg;
 		}
 	}
+	return src;
 }
 
 static int
@@ -211,17 +214,15 @@ rewrite(void)
 			Rule *r = NULL;
 			if(c == '<' && s[1] == '>') { /* rule */
 				r = rules_++, r->id = rules_ - rules - 1;
-				r->a = dict_, s = parse_frag(s + 2);
-				r->b = dict_, s = parse_frag(s);
-				compile_rule(r);
+				s = compile_rule(r, s + 2);
 				while(*s == ' ') s++;
 				return write_rule(r, s, 1);
 			}
 			if(c == '?' && s[1] == '(') { /* lambda */
-				cap = walk(s + 1), lambda.id = -1;
-				lambda.a = dict_, s = parse_frag(s + 2);
-				lambda.b = dict_, parse_frag(s), s = cap;
-				compile_rule(&lambda);
+				cap = walk(s + 1);
+				r = &lambda, r->id = -1;
+				compile_rule(r, s + 2);
+				s = cap;
 				while(*s == ' ') s++;
 				return apply_rule(&lambda, s);
 			}