[ruby-core:86780] [Ruby trunk Feature#6284] Add composition for procs

Issue #6284 has been updated by baweaver (Brandon Weaver).


I just realized that infix operators evaluate before `to_proc`, allowing something like this:

```ruby
[1,2,3].map(&:succ.to_proc >> :to_str.to_proc)
```

Codified it into a gem for kicks: https://github.com/baweaver/mf

----------------------------------------
Feature #6284: Add composition for procs
https://bugs.ruby-lang.org/issues/6284#change-71738

* Author: pabloh (Pablo Herrero)
* Status: Feedback
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
----------------------------------------
=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)


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