From: dblack@...
Date: 2006-10-06T04:33:55+09:00
Subject: Re: question mark at end of method name

Hi --

On Fri, 6 Oct 2006, Paul Lutus wrote:

> py wrote:
>
>> what does the question mark at the end of a method name represent?
>>
>> for example:
>>
>> x = "something"
>> break if x.empty?
>>
>> i've seen what ! does....what is ?
>
> .empty? means "is it empty?". It tries to suggest that a question is being
> asked. It's unfortunate that the "!" syntax, which seems similar, actually
> means "apply the result to the present object."

Actually the ! at the end of a method name means, according to Matz,
that it's a "dangerous" method; and such methods always (in the core
at least) exist in a pair with a non-!, non-dangerous method of the
same name.

"Danger" in this context can mean receiver-changing, and often does
mean that, but it doesn't have to.


David

-- 
                   David A. Black | dblack@wobblini.net
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org