From: Gavin Sinclair <gsinclair@...>
Date: 2004-08-03T22:08:29+09:00
Subject: Re: Request for two methods in Array class

On Tuesday, August 3, 2004, 10:59:57 PM, David wrote:

> Hi --

> On Tue, 3 Aug 2004, Yukihiro Matsumoto wrote:

>> Hi,
>> 
>> In message "Request for two methods in Array class"
>>     on 04/08/03, Mike Hall <mghallNO@SPAMenteract.com> writes:
>> 
>> |1. A new method, Array.combine  (needs a better name for general use).
>> |   It takes entries from two (or many) arrays and combines them.
>> |   (like a combination of Array.zip, fetch, and map)
>> 
>> Sounds nice.  But I'm not sure "combine" is a proper name for the
>> method.   We need more discussion, for example:

> I know I'm being the voice of possibly excessive conservatism
> here... but I'm just wondering what this method would give us, since
> we can already do zip+map.  As Ara said, it would create one less
> object.  But chaining methods always creates intermediate objects.  If
> zip+map deserves to be combined into a new, single method, what about
> flatten+map, or compact+map?  And then (flatten+map)+compact....

> I realize that zip+map is more likely to be actually used, and people
> have often said they wish zip's block mapped the elements.  But I
> still wonder whether it's worth a new method and method name.

That's good thinking.  The most compelling examples so far have been
the ones where #zip actually has map-like functionality.  No need for
a new method.  *Definitely* don't touch #map !!

  arr.zip { ... }            # same behaviour as arr.map { ... }
  arr.zip(x) { ... }         #  "    "    "   "  arr.zip(x).map { ... }
  etc.
  
Gavin