[ruby-dev:50829] [Ruby master Bug#7877] E::Lazy#with_index should be lazy

Issue #7877 has been updated by jeremyevans0 (Jeremy Evans).

File lazy-with-index-block-7877.patch added

This bug is still present in the master branch.  I've updated nobu's patch to apply to the master branch, which required a significant rewrite.  The updated patch is attached.

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Bug #7877: E::Lazy#with_index should be lazy
https://bugs.ruby-lang.org/issues/7877#change-80500

* Author: shyouhei (Shyouhei Urabe)
* Status: Assigned
* Priority: Normal
* Assignee: nobu (Nobuyoshi Nakada)
* Target version: 
* ruby -v: 2.1.0-dev
* Backport: 2.0.0: UNKNOWN
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=begin
So I wanted some real benefit of being lazy.  I wrote a Leibniz formula:

  def leibniz(n)
    (0..Float::INFINITY).lazy.with_index {|i, j| (-1 ** j) / (2*i+1).to_f }.take(n).reduce(:+)
  end

But it doesn't work (well, it does, indeed. It just doesn't stop working).  I got frustrated.
How about it?  Don't you feel it nifty?

Of course I can wait for the release next to 2.0.0.
=end

---Files--------------------------------
0001-enumerator.c-Enumerator-Lazy-with_index.patch (3.33 KB)
lazy-with-index-block-7877.patch (4.08 KB)


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