From: dblack@...
Date: 2006-12-24T06:19:18+09:00
Subject: Re: Help with a ruby idiom

Hi --

On Sun, 24 Dec 2006, M. Edward (Ed) Borasky wrote:

> dblack@wobblini.net wrote:
>> Hi --
>> 
>> On Sun, 24 Dec 2006, M. Edward (Ed) Borasky wrote:
>> 
>>> Might I be a curmudgeon on this Christmas eve eve? I say that any idiom 
>>> that's confusing enough that its semantics isn't *instantly* recognizable 
>>> to an old FORTRAN programmer like my curmudgeonly self probably doesn't 
>>> contribute to code readability. :) So I would write this out in "longhand" 
>>> and not let the parser have an opportunity to confuse me. So my "idiom" 
>>> would be
>>> 
>>> if (!a) then
>>> a = b
>>> end
>> 
>> That won't work though:
>> 
>> ruby -e 'if (!a) then a = b end'
>> -e:1: undefined local variable or method `a' for main:Object
>> (NameError)
>> 
>> because of the forward reference to a.
>> 
>>> Or, since my curmudgeonly self has managed to learn Perl, :)
>>> 
>>> a = b if !a
>> 
>> ||= is used a lot in Perl, too :-)  I guess I'm just used to it; my
>> eye takes it in pretty readily.
>> 
>> 
>> David
>> 
> Does this Perl-ism work?
>
> if (!defined(a)) then
> a = b
> end

Yes, but in Ruby it's defined? rather than defined.


David

-- 
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