[ruby-core:77599] [Ruby trunk Feature#6284] Add composition for procs

[duerst@it.aoyama.ac.jp]

Issue #6284 has been updated by Martin Dürst.


Paul Mucur wrote:
> Yukihiro Matsumoto wrote:
> > Positive about adding function composition. But we need method name consensus before adding it?
> > Is `#*` OK for everyone?
> 
> Aside from implementation details, is the lack of consensus on the method name (and the resulting behaviour re left vs right operand) the main blocker here?

If Matz says so, then yes, this is the main blocker.

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Feature #6284: Add composition for procs
https://bugs.ruby-lang.org/issues/6284#change-60868

* 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)


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