From: Kirk Haines <wyhaines@...>
Date: 2010-01-27T05:24:42+09:00
Subject: Re: Why does Regexp::escape backslash spaces?!?

On Tue, Jan 26, 2010 at 1:12 PM, Marnen Laibow-Koser <marnen@marnen.org> wrote:
> $ ruby -v
> ruby 1.8.7 (2008-08-11 patchlevel 72) [universal-darwin10.0]
> $ irb
> irb(main):001:0> Regexp::escape('a b')
> => "a\\ b"
>
> Why?  This doesn't seem to make any sense.  Is it a bug?

It is intentional.  In re.c:rb_reg_quote()

        switch (c) {
          case '[': case ']': case '{': case '}':
          case '(': case ')': case '|': case '-':
          case '*': case '.': case '\\':
          case '?': case '+': case '^': case '$':
          case ' ': case '#':
          case '\t': case '\f': case '\n': case '\r':
            goto meta_found;
        }


And then down in meta_found:

          case ' ':
            *t++ = '\\';
            *t++ = ' ';
            continue;


Kirk Haines