Issue #6594 has been updated by rosenfeld (Rodrigo Rosenfeld Rosas).


@trans it really helps attaching an useful example from a real world situation where functors would make it easier to implement some feature than using current Ruby features.

Good luck on trying to convince people to spend their time learning a new concept without first getting them interested on this new feature by providing a really great example usage.
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Feature #6594: Integrated Functor
https://bugs.ruby-lang.org/issues/6594#change-27266

Author: trans (Thomas Sawyer)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 2.0.0


=begin
I know the developers meeting is coming up so I'd like to get a few ideas I've had sitting in the wings out in the air before then.

One the more useful is the idea of integrating Functors directly into the language. "Functor" is the term I use for "higher-order function".

I blogged about this idea and you can read it here: http://trans.github.com/2011-09-07-ruby-heart-higher-order-functions/

The super short version is this:

  def f => op, arg
    arg.send(__op__, arg)
  end

  f + 3  #=> 6
  f * 3  #=> 9

Another example:

  class String
    def file => op, *args
      File.send(__op__, self, *args)
    end
  end

  "README.rdoc".file.mtime  #=> 2012-06-14 12:34:45 -0400

I'm using `=>` as means of indicating a higher-order function. Of course another syntax could be used if this won't fly. The important thing is the idea of higher-order functions being integrated directly into the language. Doing this without that integration requires the creation of an intermediate object for each call which is very inefficient.
=end



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