[ruby-core:77336] [Ruby trunk Feature#2172] Enumerable#chunk with no block

Issue #2172 has been updated by Marc-Andre Lafortune.

Assignee changed from Akira Tanaka to Yukihiro Matsumoto

Matz, would you agree to return enumerator for `chunk` with a block?
This is useful in particular to chain it with `with_index`

A real case example is to summarize a list of integers into ranges. Currently, we need:

    integers.enum_for(:chunk).with_index { |x, idx| x - idx }.map do |diff, group|
      [group.first, group.last]
    end

Ref: http://stackoverflow.com/questions/8621733/how-do-i-summarize-array-of-integers-as-an-array-of-ranges

----------------------------------------
Feature #2172: Enumerable#chunk with no block
https://bugs.ruby-lang.org/issues/2172#change-60582

* Author: Marc-Andre Lafortune
* Status: Assigned
* Priority: Normal
* Assignee: Yukihiro Matsumoto
----------------------------------------
=begin
 What should "(1..3).chunk" (i.e. without a block) do?
 
 It issued an
 ArgumentError: tried to create Proc object without a block
 
 I changed the error message to "no block given" which I hope to be more informative, but maybe there is something more useful to do here?
 
 A default block of {|x| x} doesn't seem all that useful.
 
 Returning an enumerator that, upon completion, will return an enumerator would probably be better, but could also be a bit confusing if someone doesn't realize he forgot to specify the block?
 
 Thanks to Run Paint for raising the question when writing the rubyspec for #chunk.
=end




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