From: shibata.hiroshi@... Date: 2014-01-30T06:16:46+00:00 Subject: [ruby-dev:47932] [ruby-trunk - Bug #7877] E::Lazy#with_index should be lazy Issue #7877 has been updated by Hiroshi SHIBATA. Target version changed from 2.1.0 to current: 2.2.0 ---------------------------------------- Bug #7877: E::Lazy#with_index should be lazy https://bugs.ruby-lang.org/issues/7877#change-44758 * Author: Shyouhei Urabe * Status: Assigned * Priority: Normal * Assignee: Yutaka HARA * Category: core * Target version: current: 2.2.0 * ruby -v: 2.1.0-dev * Backport: 2.0.0: UNKNOWN ---------------------------------------- =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) -- http://bugs.ruby-lang.org/