From: dblack@...
Date: 2006-07-21T20:30:26+09:00
Subject: opacity of magic enumerator (was: Re: Using .each with constructors)

Hi --

On Fri, 21 Jul 2006, Logan Capaldo wrote:

>
> On Jul 20, 2006, at 7:32 PM, transfire@gmail.com wrote:
>
>> Hmm...It's too bad that #times below returns 3. It be pretty neat if it
>> acted like #map in this respect instead.
>>
>>  3.times { Object.new }
>> 
>
> irb(main):001:0> RUBY_VERSION
> => "1.9.0"
> irb(main):002:0> a, b, c = 3.times.map { Object.new }
> => [#<Object:0x2382c8>, #<Object:0x2381d8>, #<Object:0x238070>]

Interesting....  That reveals that one of the problems with this magic
enumerator thing is that the method names weren't necessarily chosen
with this in mind, and don't work very well.  3.times.map very
strongly does *not* communicate a 0...3 mapping to me.  My first
reading is:

    3.map

since I expect 3.times to return 3.  My second reading is:

   3.times { map { Object.new } }

which also makes no sense.  It's quite a leap to figure out that it
means:

   (0...3).map { Object.new }

I fear the magic enumerator doesn't sit very well with the language as
designed without it.


David

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