From: matz@... (Yukihiro Matsumoto)
Date: 2000-04-01T23:24:27+09:00
Subject: [ruby-talk:02331] Re: Function of Array.filter surprises me

Hi,

In message "[ruby-talk:02330] Function of Array.filter surprises me"
    on 00/04/01, mrilu <mrilu@ale.cx> writes:

|I don't expect Array.filter to do task of Array.replace_with!.
|I would expect it to be alias for Enumerable.select (or it's alias 
|find_all), that is filter or select all the elements satisfying
|given condition.

I have to admit `filter' is not a best name; some proposed `collect!',
but I don't feel it's not collecting anything.

|Moreover it is change-in-place function so wonder where lurks missing
|exclamation mark? As you see, Enumerable.select don't need any
|exclamation, so illusory connection between these two is even greater.

Unlike Scheme, not all change-in-place functions are named with
exclamation mark.  In Ruby, exclamation mark means `MORE dangerous',
or `may cause surprise' than non-bang counterpart, i.g. in-place
modification by `gsub!' may let you surprise, comparing copying
`gsub'.

|I could add that Enumerable.apply would be better name for collect, IMO.
|And that Enumerable (among other things) is very nice, indeed.

The names collect/select/detect is from Smalltalk.  I feel the name
`apply' focuses too much on side effect.

							matz.