Slightly improve \w width measurements:

Count special characters with the same width as ASCII characters
and treat all other escape sequences as if they had a width of 0.
Certainly not perfect, but a bit better.
For example, GNU RCS ci(1) needs this; reported by naddy@.

1 files changed, 19 insertions, 1 deletions

diff --git a/roff.c b/roff.c
index 3948711e..435b0bfc 100644
--- a/roff.c
+++ b/roff.c
@@ -1004,8 +1004,9 @@ roff_res(struct roff *r, struct buf *buf, int ln, int pos)
 
 		/* Advance to the end of the name. */
 
+		naml = 0;
 		arg_complete = 1;
-		for (naml = 0; maxl == 0 || naml < maxl; naml++, cp++) {
+		while (maxl == 0 || naml < maxl) {
 			if (*cp == '\0') {
 				mandoc_msg(MANDOCERR_ESC_BAD, r->parse,
 				    ln, (int)(stesc - buf->buf), stesc);
@@ -1016,6 +1017,23 @@ roff_res(struct roff *r, struct buf *buf, int ln, int pos)
 				cp++;
 				break;
 			}
+			if (*cp++ != '\\' || stesc[1] != 'w') {
+				naml++;
+				continue;
+			}
+			switch (mandoc_escape(&cp, NULL, NULL)) {
+			case ESCAPE_SPECIAL:
+				/* FALLTHROUGH */
+			case ESCAPE_UNICODE:
+				/* FALLTHROUGH */
+			case ESCAPE_NUMBERED:
+				/* FALLTHROUGH */
+			case ESCAPE_OVERSTRIKE:
+				naml++;
+				break;
+			default:
+				break;
+			}
 		}
 
 		/*