From: Michael Selig <michael.selig@...>
Date: 2008-09-19T12:58:26+09:00
Subject: [ruby-core:18721] Re: Encoding Safe Regexp.escape()

On Fri, 19 Sep 2008 06:48:41 +1000, James Gray <james@grayproductions.net>  
wrote:

> As part of my ongoing process to make CSV m17n savvy, I'm needing an  
> encoding safe Regexp.escape().  I'm currently using basically this code:
>
>    @re_esc   =   "\\".encode(@encoding)
>    @re_chars =   %w[ \\ . [ ] ^ $ ?
>                      *  + { } ( ) | ].map { |s| s.encode(@encoding) }
>
>    # ...
>
>    def escape_re(str)
>      str.chars.map { |c| @re_chars.include?(c) ? @re_esc + c : c }.join
>    end
>
> First question:  are there logic flaws there or is escaping a string to  
> safely use in a Regexp that simple?

Just for fun, I ran:

ruby -e 'p ("\x00".."\x7f").select {|c| c != Regexp.escape(c)}'

and got:

["\t", "\n", "\v", "\f", "\r", " ", "#", "$", "(", ")", "*", "+", "-",  
".", "?", "[", "\\", "]", "^", "{", "|", "}"]

so it looks like Regexp#escape is escaping more that your code does.

Cheers
Mike