Re: Preventing submatch from eating backslashes

On Fr, 12 Mär 2010, Christian Brabandt wrote:

> I just found out, that submatch eats my backslashes. Consider this
> example:
> ~$ gvim -u NONE -N -c ":put ='foo\bar'" -c ":%s/.\+/\=submatch(0)/"
>
> which gives you foobar instead of foo\bar.
>
>
> Is there an easy way to prevent this without having me to remember, that
> I need to escape submatch, just because it could contain backslashes?
>
> I know that \0 works correctly, but I need to call a function in the
> replacement part.

I believe this bug is also mentioned in the todo list:
submatch() may remove backslash. (Sergey Goldgaber, 2009 Jul 6)

So here is a patch, that fixes it, I believe. I don't know the source
well enough to judge, whether this is the correct solution. But at
least, this works for me™

chrisbra t41:~/vim/src [1093]% hg diff
diff -r 907cf09fbb32 src/regexp.c
--- a/src/regexp.c Tue Mar 02 18:16:09 2010 +0100
+++ b/src/regexp.c Mon Mar 22 10:13:51 2010 +0100
@@ -7329,6 +7329,8 @@
retval = vim_strnsave(s, (int)(submatch_match->endp[no] - s));
}

- return retval;
+ /* Parsing the \= expression in the substitution part will later on
+ * remove all backslashes. Therefore, we need to protect them here */
+ return vim_strsave_escaped(retval, (char_u *)"\\");
}