ed

commit 1438d2c20405a651964e0f454d2037db1c91a22f
parent 19b5ef27501528a6f1f9c5b9127ec41856afb7aa
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sun, 13 Dec 2015 13:04:12 +0100

Add support for backreferences in addsub()

This support is for substitution patterns like
a\1a.

Diffstat:
M
ed.c
 | 
15
+++++++++++++--

1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/ed.c b/ed.c
@@ -885,16 +885,27 @@ static void
 addsub(char **s, size_t *cap, size_t *siz)
 {
 	char *end, *q, *p, c;
+	int sub;
 
 	for (p = rhs; c = *p; ++p) {
 		switch (c) {
 		case '&':
-			q   = lastmatch + matchs[0].rm_so;
-			end = lastmatch + matchs[0].rm_eo;
+			sub = 0;
+			goto copy_match;
+		case '\\':
+			if ((c = *++p) == '\0')
+				return;
+			if (!isdigit(c))
+				goto copy_char;
+			sub = c - '0';
+		copy_match:
+			q   = lastmatch + matchs[sub].rm_so;
+			end = lastmatch + matchs[sub].rm_eo;
 			while (q < end)
 				*s = addchar(*q++, *s, cap, siz);
 			break;
 		default:
+		copy_char:
 			*s = addchar(c, *s, cap, siz);
 			break;
 		}