[Open] Object#as

Issue #10094 has been reported by Akira M…


Feature #10094: Object#as
https://bugs.ruby-lang.org/issues/10094

  • Author: Akira M.
  • Status: Open
  • Priority: Normal
  • Assignee:
  • Category: core
  • Target version: current: 2.2.0

We’ve had numbers 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]