[ruby-core:80943] [Ruby trunk Feature#10095] Object#as

Issue #10095 has been updated by janosch-x (Janosch M端ller).


The weakness of "as" is that it is not a verb. This puts it at odds with the majority of core methods and makes it confusing when followed up by more method calls.

Without a follow-up it is indeed quite readable:

`number.as { |x| x ** 2 }`

Treat the number as it's square. Fair enough!

With more stuff chained, though, it becomes confusing, because a sentence like "Treat A as B" has a certain finality to it. In a natural language you would not say something like "Treat A as B as C". Thus a longer chain becomes hard to read:

`number.as { |x| x ** 2 }.next.as { |x| x ** 2 } # => 10201`

Using a verb instead makes it much easier to visualize the flow of events:

`number.convert { |x| x ** 2 }.next.convert { |x| x ** 2 }`

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Feature #10095: Object#as
https://bugs.ruby-lang.org/issues/10095#change-64601

* Author: matsuda (Akira Matsuda)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
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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]

---Files--------------------------------
itself-block.patch (1.35 KB)


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