From: matz@... Date: 2018-05-17T05:56:50+00:00 Subject: [ruby-core:87100] [Ruby trunk Feature#6284][Open] Add composition for procs Issue #6284 has been updated by matz (Yukihiro Matsumoto). Status changed from Feedback to Open Considering the combination of OOP and FP, it seems a good idea to adding both forward and reverse combination of procs. So we pick Groovy way (adding `<<` and `>>` methods to `Proc`). We need more discussion if we would add combination methods to the `Symbol` class. Matz. ---------------------------------------- Feature #6284: Add composition for procs https://bugs.ruby-lang.org/issues/6284#change-72069 * Author: pabloh (Pablo Herrero) * Status: Open * Priority: Normal * Assignee: matz (Yukihiro Matsumoto) * Target version: ---------------------------------------- It would be nice to be able to compose procs like functions in functional programming languages: ```ruby to_camel = :capitalize.to_proc add_header = ->val {"Title: " + val} format_as_title = add_header << to_camel << :strip ``` instead of: ```ruby format_as_title = lambda {|val| "Title: " + val.strip.capitalize } ``` It's pretty easy to implement in pure ruby: ```ruby class Proc def << block proc { |*args| self.call( block.to_proc.call(*args) ) } end end ``` ---Files-------------------------------- 0001-proc.c-Implement-Proc-for-Proc-composition.patch (3.65 KB) 0002-proc.c-Implement-Method-for-Method-composition.patch (2.67 KB) 0003-proc.c-Support-any-callable-when-composing-Procs.patch (3.97 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: