From: "David A. Black" <dblack@...>
Date: 2007-11-15T22:41:57+09:00
Subject: Re: alias_method :tap, :affect

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Hi --

On Thu, 15 Nov 2007, Pe=F1a, Botp wrote:

> From: furtive
> # On Nov 12, 2:31 pm, Martin
> # > #tap is the opposite use case - you want to "tap" the object stream,
> # > observing without affecting.
> # OK I understand Object#tap now.  At first I thought the motivation was
> # to modify the object inside the block, but now I see that it can be a
> # useful part of functional-style ruby.
> # So, to throw this out again --- there should also be Object#as which
> # returns the block result (I like the name 'as' but I am not
> # particularly attached to it).  I can personally attest to its
> # usefulness, and I can show reams of examples in addition to the above
> # one I gave.
>
> (my previous message seems to have lost, so i apologize for a 2nd post)
>
> tap is indispensable for me when it comes to chaining (specially bang met=
hods)..
>
> naive example follows...
>
> ~> s
> =3D> "This is a test"
>
> ~> s.capitalize!.capitalize!
> NoMethodError: undefined method `capitalize!' for nil:NilClass
>
> breaks!
>
> ~> s.upcase!.upcase!
> =3D> nil
>
> breaks!
>
> ~> s.upcase!.capitalize!
> NoMethodError: undefined method `capitalize!' for nil:NilClass
>
> breaks!
>
> ~> s.tap(&:upcase!).tap(&:upcase!).tap(&:capitalize!).tap(&:capita
> lize!).tap(&:downcase!).tap(&:downcase!)
> =3D> "this is a test"
>
> long chain, no break :)
>
> btw, i like the #tap name, it's like tapping a chain so that it wont brea=
k. (i'm not an english expert but that is how i usually use the word)..

I am an English expert and I have no idea what "tap" is supposed to
have to do with what this #tap method does.


David

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