From: "nobu (Nobuyoshi Nakada)" <nobu@...>
Date: 2012-08-03T11:45:53+09:00
Subject: [ruby-core:46955] [ruby-trunk - Feature #6824] StopIteration gets a source method


Issue #6824 has been updated by nobu (Nobuyoshi Nakada).

Description updated

You should use assert_same instead of assert_equal, I think.

----------------------------------------
Feature #6824: StopIteration gets a source method
https://bugs.ruby-lang.org/issues/6824#change-28618

Author: jasiek (Jan Szumiec)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 2.0.0


=begin
I'd like to add a method to StopIteration that returns an instance of the enumerator which triggered this exception. Eg:

  enum = [].each
  begin
    enum.next
  rescue StopIteration => ex
    puts "same" if ex.source == enum
  end

This is useful when you're merging multiple collections using min/max - when one of the collections is exhausted it can be easily ignored.

  enumerators = 100.times.map do
    rand(100).times.map do
      rand
    end.sort.each
  end

  merged = []
  while !enumerators.empty?
    begin
      enumerators.map(&:peek)
      values = enumerators.map(&:next)

      merged += values.sort
    rescue StopIteration => e
      enumerators.delete(e.source)
      retry
    end
  end

  fail unless merged != merged.sort

Attached is a patch against trunk.
=end




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