From: sawadatsuyoshi@...
Date: 2014-07-28T02:30:07+00:00
Subject: [ruby-core:64089] [ruby-trunk - Feature #10095] Object#as

Issue #10095 has been updated by Tsuyoshi Sawada.


What about unifying this feature with this feature: https://bugs.ruby-lang.org/issues/6373? Let the block be optional; when there is one, it returns what this thread originally expected, and when there is no block, it returns the receiver. In that case, a name like `self_by` may make sense.

    [1, 2, 3, 4].select(&:odd?).self_by{|x| {total: x.count, data: x}}

    [1, 2, 3, 2, 2, 1].group_by(&:self_by)

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Feature #10095: Object#as
https://bugs.ruby-lang.org/issues/10095#change-48101

* Author: Akira Matsuda
* Status: Open
* Priority: Normal
* Assignee: 
* Category: core
* Target version: current: 2.2.0
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We've had so many times of feature requests for a method similar to Object#tap that doesn't return self but returns the given block's execution result (e.g. #7388, #6684, #6721 ).

I'm talking about something like this in Ruby of course:
Object.class_eval { def as() yield(self) end }

IIRC Matz is not against introducing this feature but he didn't like any of the names proposed in the past, such as embed, do, identity, ergo, reference, yield_self, itself, apply, map, tap!, etc.

So, let us propose a new name, Object#as today.
It's named from the aspect of the feature that it gives the receiver a new name "as" a block local variable.
For instance, the code reads so natural and intuitive like this:

(1 + 2 + 3 + 4).as {|x| x ** 2}
=> 100

Array.new.as {|a| a << 1; a << 2}
=> [1, 2]



-- 
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