From: Brian Candler <B.Candler@...>
Date: 2003-05-13T16:51:08+09:00
Subject: Re: Regexp: why does (re)* return only last repetition?

On Tue, May 13, 2003 at 04:10:36PM +0900, Brian Candler wrote:
> And single-quoted strings have the same issue it turns out:
> 
>           a = '\\'
>           p a.length   # => 1
> 
> I am not sure why that should be, since '\n'.length is 2. I think you may
> have uncovered a bug here.

I just realised, it's not a bug: it's necessary to give a mechanism for
inserting a single quote within a single-quoted string. This is done by
escaping it with backslash:

          '\''.length     #>> 1   (just a single quote)

But that in turn means that to get a literal backslash it also needs to be
escaped:

          '\\'.length     #>> 1   (just a backslash)

All other backslash-X sequences are inserted as the backslash and the X.

Regexps are subject to certain quoting rules too. Try:

    z = /ab\c/
    puts z.inspect

This program crashes under both ruby 1.6 ("unterminated regexp meets end of
file) and 1.8 ("unterminated string meets end of file").

But z = /ab\d/ works. Somebody care to explain that one? :-)

Regards,

Brian.