From: nobu@...
Date: 2014-08-02T14:18:50+00:00
Subject: [ruby-core:64162] [ruby-trunk - Feature #6817] Partial application

Issue #6817 has been updated by Nobuyoshi Nakada.

Description updated

Michael Kohl wrote:
> In that case, how about making `Symbol#to_proc` accept additional arguments?
> 
> ~~~ruby
> (1..3).map(:+, 2) 
> ~~~

It doesn't relate to `Symbol#to_proc`.

----------------------------------------
Feature #6817: Partial application
https://bugs.ruby-lang.org/issues/6817#change-48165

* Author: Michael Kohl
* Status: Open
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* Category: core
* Target version: next minor
----------------------------------------
I know that what I propose here is a significant change to Ruby, but it's part of my ongoing quest to get some more functional programming features into Ruby (see also #4539 and #6373).

I was wondering if  it would make sense to maybe introduce partial application to Ruby?  So that instead of

~~~ruby
(1..3).map { |i| i + 2 }
~~~

or the somewhat unwieldy

~~~ruby
(1..3).map(&2.method(:+))
~~~

one could just write

~~~ruby
(1..3).map(&2.+)
~~~

which I think has a quite rubyish feel to it. I have a POC implementation in Ruby (I tried it with various `Fixnum` methods) over at [my blog](http://citizen428.net/blog/2012/07/30/ruby-left-section-for-infix-operators), but that was just a quick hack and obviously I don't want to monkey-patch every method with arity 1, but it was a  nice way of exploring possible syntax.




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