From: David Flanagan <david@...>
Date: 2007-12-21T06:56:45+09:00
Subject: Re: named captures assigning to local variables

Tanaka Akira wrote:
> In article <S2445477AbXLTQsI/20071220164808Z+24367@swip003.ftl.affinity.com>,
>   David Flanagan <david@davidflanagan.com> writes:
> 
>> How about making the return value an array of the captured strings, or nil 
>> if there was no match? 
> 
> Another idea is $~, which is a MatchData or nil.

That's simpler to implement than what I had done.  And in the simple 
case when all capturing groups have names, $~ behaves like an array of 
the captured values, doesn't it?  I think I like this.

Another option is to raise an exception if the match fails.  I can 
almost convince myself that this is the right thing to do for this kind 
of assignment...  But Ruby is usually more forgiving, so probably not.

Another option is to return an empty array when the pattern fails to 
match, indicating that no values were assigned.  This follows the 
example of:

    x,y = []

But then you'd have to test the return value with empty? and would have 
to surround the assignment with parentheses, so the syntax becomes much 
less pleasant.

	David