From: furtive.clown@...
Date: 2007-11-13T06:25:16+09:00
Subject: Re: alias_method :tap, :affect

On Nov 12, 3:55 pm, James Edward Gray II <ja...@grayproductions.net>
wrote:
> On Nov 12, 2007, at 2:40 PM, furtive.cl...@gmail.com wrote:
>
> I guess I want to see some more examples, because I'm seriously
> doubting the usefulness.  The example you showed so far was using it
> to create this:
>
>     platform_audio_files = audio_stems.map { |f|
>        f + "." + audio_ext[platform]
>     }.as { |t|
>        t + audio_basenames
>     }.map { |f|
>        File.join(audio_dir, f)
>     }
>
> instead of:
>
>     platform_audio_files = (audio_stems.map { |f|
>        f + "." + audio_ext[platform]
>     } + audio_basenames).map { |f|
>        File.join(audio_dir, f)
>     }
>
> I don't really understand what the problem is with the second version
> that's shorter and easier for me to understand.  If it's the need to
> introduce some parentheses into the call chain, we can fix that:
>
>     platform_audio_files = audio_stems.map { |f|
>        f + "." + audio_ext[platform]
>     }.concat(audio_basenames).map { |f|
>        File.join(audio_dir, f)
>     }
>
> So yes, please send more examples as I remain unconvinced.

It was only a coincidence that you found an Array method which
corresponded to the operation in the block, namely Array#concat.  Your
example breaks down once the operation is nontrivial --- something
more complex than '+'.

We can also introduce temporaries inside the block without causing
distraction in the outer scope.  The purpose of the block chain is to
produce a value for platform_audio_files; a flood temporary variables
on the same scope obscures this purpose.