From: Robert Klemme <shortcutter@...>
Date: 2010-06-07T20:46:39+09:00
Subject: Re: inject method of Array class

2010/6/7 David A. Black <dblack@rubypal.com>:

> On Mon, 7 Jun 2010, Rein Henrichs wrote:
>
>> On 2010-06-06 17:55:58 -0700, David A. Black said:

>> I suspect that the majority are overwritten for performance reasons,
>> although some of them surprise me as well.
>>
>> A linked list, for instance, would have a constant time #count because
>> that state is kept on the list object and doesn't require an O(n)
>> enumeration of the members.
>
> I think it's a mixture of performance reasons and things like what it
> should return if there's no block (like Enumerable#map always
> returning an array vs. Array#map returning its receiver). Array is
> definitely the one that has the most overrides, with Hash coming in
> second at 6 and IO having none.

David, I guess you meant to write "... vs. Array#map! returning its
receiver"?  Note the exclamation mark.  Array#map returns a new Array
on every invocation.

Kind regards

robert

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