From f139f3218e0f8a74abd2c42908b38c79b01d4cee Mon Sep 17 00:00:00 2001
From: Devine Lu Linvega <aliceffekt@gmail.com>
Date: Sat, 20 Apr 2024 11:09:43 -0700
Subject: [PATCH] Do not injest register on empty put_reg

---
 src/modal.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/src/modal.c b/src/modal.c
index 3b654cd..fd5e6e5 100644
--- a/src/modal.c
+++ b/src/modal.c
@@ -48,12 +48,7 @@ set_reg(int r, char *b)
 static void
 put_reg(char r)
 {
-	char c, *s = regs[(int)r], *ss;
-	if(!s) {
-		*dst_++ = '?', *dst_++ = r;
-		return;
-	}
-	ss = walk(s);
+	char c, *s = regs[(int)r], *ss = walk(s);
 	if(r == '*') {
 		int i, depth = 0;
 		if(*s == '(') { /* special explode tuple */
@@ -142,7 +137,7 @@ write_rule(Rule *r, char last, char *res)
 {
 	char c, *b = r->b, *origin = dst_;
 	while((c = *b++))
-		if(spacer(last) && c == '?')
+		if(spacer(last) && c == '?' && regs[(int)*b])
 			put_reg(*b++);
 		else
 			*dst_++ = c, last = c;
@@ -222,7 +217,7 @@ main(int argc, char **argv)
 		return !printf("usage: modal [-vqn] source.modal\n");
 	for(i = 1; i < argc && *argv[i] == '-'; i++) {
 		switch(argv[i][1]) {
-		case 'v': /* version */ return !printf("Modal Interpreter, 19 Apr 2024.\n");
+		case 'v': /* version */ return !printf("Modal Interpreter, 20 Apr 2024.\n");
 		case 'q': /* quiet */ fclose(stderr); break;
 		case 'n': /* infinite */ cycles = 0xffffffff; break;
 		}