From: "David A. Black" <dblack@...>
Date: 2005-10-08T11:00:50+09:00
Subject: Re: select! not present but reject! is

Hi --

On Sat, 8 Oct 2005, Gavin Sinclair wrote:

> David A. Black wrote:
>> On Sat, 8 Oct 2005, Jacob Fugal wrote:
>>
>>> On 10/7/05, Mark Hubbart <discordantus@gmail.com> wrote:
>>>
>>>> Also, I'm not really advocating any action here. I'm just suggesting
>>>> that it would be a little weird for "select!" to be the exact opposite
>>>> of "reject!", since the Ruby definitions wouldn't stand up to the
>>>> English ones.
>>>
>>> I'll concede that, but IMNSHO consistency between the non-bang and
>>> bang versions seems more important.
>>
>> The most important thing, though, is that every method name be
>> appropriate.  If select! ("dangerous select") is the best way to
>> communicate the "delete unless..." process, then it's right.  If not,
>> then not.  It's reasonable to expect that a/b == a!/b! -- but the
>> existence of a, b, and a! doesn't mean that b! is a good method name
>> for the inverse of a!.
>
> Perhaps not, but in this case, inconsistency would be unforgivable.

As I've said repeatedly, I am *not* suggesting that Ruby adopt a
select! method that does something other than the opposite of reject!.
I am suggesting that Ruby *not* adopt a select! method at all, because
select! is (in my view) a bad name for a method that does the opposite
of reject!, and having it do anything else would be confusing.

> You should be able to predict how a method will work based on your
> knowledge of how other, similar methods work.
>
> In this case it's absolutely clear.

See earlier in thread -- there's been a lot of discussion and
disagreement.

>  arr = (1..10).to_a
>  arr.select! { |n| n % 2 == 0 }  # -> arr == [1,3,5,7,9]; self is
> returned
>
> It's a no-brainer.  Consistency is paramount!

Your select! works exactly like reject!.  That might be a bit too much
consistency :-)


David

-- 
David A. Black
dblack@wobblini.net