From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-03-27T03:32:11+09:00
Subject: [ruby-core:43719] [ruby-trunk - Feature #5389][Assigned] New method Enumerator#iterate


Issue #5389 has been updated by mame (Yusuke Endoh).

Status changed from Open to Assigned
Assignee set to matz (Yukihiro Matsumoto)


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Feature #5389: New method Enumerator#iterate
https://bugs.ruby-lang.org/issues/5389#change-25221

Author: yimutang (Joey Zhou)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: 
Target version: 


If we want to iterate over the elements of a enumerable object with *multiple* blocks, we can use the Enumerator class.

A method 'iterate' is required, we can write it in Ruby:

    class Enumerator
      def iterate
        yield_value = self.next
        return_value = yield yield_value
        self.feed return_value
        self
      end
    end

Well, here is an example:

    array = (1..10).to_a
    enum = array.map!

    loop do
      enum.iterate {|n| n + 10 }
      enum.iterate {|n| n * 2 }
      enum.iterate {|n| -n }
    end

    p array # => [11, 4, -3, 14, 10, -6, 17, 16, -9, 20]

We want to map an array: the 1st element use blk1, the 2nd use blk2, the 3rd use blk3...

I think this Enumerator#iterate method is sometimes useful, so would you please introduce it into the language core?



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