From: Robert Klemme <shortcutter@...>
Date: 2010-01-14T20:43:22+09:00
Subject: Re: Ruby Regex

2010/1/14 Brian Candler <b.candler@pobox.com>:
> Robert Klemme wrote:
>> For me there is actually something weird about Ruby's escape handling
>> - but it's something else: in some circumstances Ruby allows you to
>> *omit* a backslash which is meant to be convenient (I believe) but
>> which leads to a certain inconsistency:
>>
>> irb(main):014:0> '\1'  # this might be seen as surprising
>> => "\\1"
>
> I think the principle is "single quoting does the absolute minimum
> amount of dequoting".

Hmm, I never thought of it that way.  I'm not sure I like this principle though.

> However it *has* to support a way to get a single-quote within a
> single-quoted string, and they chose \'. As a consequence, it *has* to
> support \\ to get a single backslash within a single-quoted string.
>
> The question then is, should any other sequence like \1 raise an error,
> or return literal \ and 1 ?

I opt for raising a syntax error.  I know, this is unlikely to happen
anytime soon if only because of the large base of code that is
potentially affected.  With what I have seen over the past years, the
number of backslashes needed for proper quoting (especially for #gsub
and friends) has caused much confusion.  I believe that could be
avoided by disallowing the '\1'.

> The alternative would have been to use two single quotes where you want
> a single quote within a string:
>
>   'It''s that time of day'
>
> I quite like that, but arguably it's just confusing in a different way.

I like the quoting approach better. :-)

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/