From: "David A. Black" <dblack@...>
Date: 2005-10-09T13:53:09+09:00
Subject: Re: bang methods

Hi --

On Sun, 9 Oct 2005, Ryan Leavengood wrote:

> On 10/8/05, David A. Black <dblack@wobblini.net> wrote:
>>
>> keep! implies keep.  I think keep (without the !) would be an inplace
>> operation already.  Or maybe keep_all { <test> }.
>
> I vote we add keep_all or keep_if, and make select! a synonym for it.
> Just like delete_if and reject!.

delete_if and reject! aren't quite synonyms, though:

irb(main):010:0> [1,2,3,4].delete_if {|x| x > 4 }
=> [1, 2, 3, 4]
irb(main):011:0> [1,2,3,4].reject! {|x| x > 4 }
=> nil

I definitely like keep_if better than select! for conditional keeping,
but because of the delete_if/reject! difference, one would expect
keep_if (or delete_unless, maybe?) to behave like delete_if rather
than like reject!.  (I know this isn't a problem if select! exists
too, but I'm still not in favor of that name for this functionality.)

> I feel symmetry and consistency is better than sticking to ideals of
> the English language. Of course I think select! makes as much sense as
> reject!, so for me it is a moot point.

"Ruby: the triumph of balance over symmetry" (my personal Ruby slogan
:-)  Not that I'm anti-symmetry -- I just like that it isn't always a
determinant.


David

-- 
David A. Black
dblack@wobblini.net