From: bigbadmath@... Date: 2016-10-09T14:30:16+00:00 Subject: [ruby-core:77534] [Ruby trunk Feature#6284] Add composition for procs Issue #6284 has been updated by Alexander Moore-Niemi. I wrote a gem with a C extension of `Proc#compose`: https://github.com/mooreniemi/proc_compose#usage What motivated me was `map f (map g xs) = map (f . g) xs`, and what I still don't understand (being a newbie to extending Ruby or understanding its internals) is that `.map(&some_proc).map(&some_other_proc)` still behaves better than `.map(&(some_proc * some_other_proc))` given my current implementation of `compose`. Although I think composition has a lot of uses, the admittedly small but free performance benefit I expected to gain was top of my list. I do think emphasis on composition suggests a somewhat different style of writing Ruby, but I think it can be a good one, actually. Paul: what's the performance of your `compose`? If I have time later I can use https://github.com/mooreniemi/graph-function to try and see. ---------------------------------------- Feature #6284: Add composition for procs https://bugs.ruby-lang.org/issues/6284#change-60805 * Author: Pablo Herrero * Status: Feedback * Priority: Normal * Assignee: Yukihiro Matsumoto ---------------------------------------- =begin It would be nice to be able to compose procs like functions in functional programming languages: to_camel = :capitalize.to_proc add_header = ->val {"Title: " + val} format_as_title = add_header << to_camel << :strip instead of: format_as_title = lambda {|val| "Title: " + val.strip.capitalize } It's pretty easy to implement in pure ruby: class Proc def << block proc { |*args| self.call( block.to_proc.call(*args) ) } end 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: