From: "trans (Thomas Sawyer)" <transfire@...>
Date: 2012-06-19T21:08:37+09:00
Subject: [ruby-core:45714] [ruby-trunk - Feature #6594] Integrated Functor


Issue #6594 has been updated by trans (Thomas Sawyer).


@prijutme4ty Your link appears to be broken, but I am glad to see your interest on HOM. I would need to know more about your callable symbols idea to know if it is HOM like Functor. My impression from your example is that it might be a type of call recorder (akin to a Spy).

I am surprised that you think Functor seems complex, when basic model is simply:

  class Functor
    def initialize(&function)
      @function = function
    end
    def method_missing(op, *args, &blk)
      @function.call(op, *args, &block)
    end
  end

For one example, probably the first I ever made, is #every. I wrote about it at https://groups.google.com/forum/?fromgroups#!topic/ruby-talk-google/zW_IDKq754A

----------------------------------------
Feature #6594: Integrated Functor
https://bugs.ruby-lang.org/issues/6594#change-27306

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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