From: andrew@...
Date: 2014-08-07T22:07:32+00:00
Subject: [ruby-core:64250] [ruby-trunk - Feature #10095] Object#as

Issue #10095 has been updated by Andrew Vit.


I thinks this should be added as an optional block on the newly added `#itself` method, and not a new method.

~~~
"ruby".itself                 #=> "ruby"
"ruby".itself(&nil)           #=> "ruby"
"ruby".itself {|s| s.upcase } #=> "RUBY"
~~~

Since there are other method names proposed here, I originally proposed the method name just `#yield` for this, but there was no feedback on that. I think it reads better than `#itself` and has symmetry with the `yield` keyword.

~~~
# yield as a noun means "the result": an object's result (its yield) is itself
"ruby".yield  #=> "ruby"

# yield as a verb means "give way to" or "produce": the object gives way to the block
"ruby".yield {|s| s.upcase } #=> "RUBY"
~~~

Was this considered, and were there objections?

----------------------------------------
Feature #10095: Object#as
https://bugs.ruby-lang.org/issues/10095#change-48239

* Author: Akira Matsuda
* Status: Open
* Priority: Normal
* Assignee: 
* Category: core
* Target version: current: 2.2.0
----------------------------------------
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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