Forum: Ruby-core [Open] Add getters for Enumerator

Issue #3714 has been updated by marcandre (Marc-Andre Lafortune).

Status changed from Feedback to Open

I can think of two use cases.

I would like to backport some Ruby 2.0 features, and the lack of 
introspection of Enumerator makes it quite difficult.

1) In Ruby 1.9, Enumerator#each does not accept arguments. This has been 
fixed in 2.0, but there is no reasonable way to monkeypatch 
Enumerator#each in 1.9. If these getters existed, that would be easy.

2) Ruby 2.0 introduces Enumerable#size. If the getters existed, it would 
have been possible to backport Enumerator#size in Ruby for 1.9 without 
monkeypatching all methods that produce enumerators.
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Feature #3714: Add getters for Enumerator
https://bugs.ruby-lang.org/issues/3714#change-35419

Author: marcandre (Marc-Andre Lafortune)
Status: Open
Priority: Low
Assignee: knu (Akinori MUSHA)
Category: core
Target version: next minor


=begin
 Given an enumerator, there is no way to know what receiver, method and 
arguments it is based upon (although one could use Enumerator#inspect 
and parse it to get the method).

 For sake of completeness and introspection, it could be useful to have 
access to them.

 This patch adds Enumerator#receiver, #method and #arguments: 
http://github.com/marcandre/ruby/commit/fd4c17f7fd

 Note that for Enumerator created with a block like Enumerator.new{|y| y 
<< 1 << 2}, then receiver is a Enumerator::Generator, method is :each 
and arguments is []. This is consistent with inspect.

 Thanks.
=end