From: philipp@... Date: 2017-11-06T15:28:56+00:00 Subject: [ruby-core:83689] [Ruby trunk Feature#14084] Introduce Enumerator#next? Issue #14084 has been updated by tessi (Philipp Tessenow). Description updated edited the code example to be a little more readable as to michael's suggestion (https://twitter.com/__michaelg/status/927541360764342272) ---------------------------------------- Feature #14084: Introduce Enumerator#next? https://bugs.ruby-lang.org/issues/14084#change-67715 * Author: tessi (Philipp Tessenow) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- I'd like to propose a new method for Enumerator which returns whether there will be a next value in the enumerator when calling `Enumerator#next`. It should work like this ruby demo: ~~~ ruby class Enumerator def next? peek true rescue StopIteration false end end a = [1,2,3] e = a.to_enum p e.next? #=> true p e.next #=> 1 p e.next? #=> true p e.next #=> 2 p e.next? #=> true p e.next #=> 3 p e.next? #=> false p e.next #raises StopIteration ~~~ I propose the method to be called `next?` as it returns either `true` or `false`. I am aware that we can currently figure out if there is a next value by using `rescue` (as in the code snippet above), but it is ugly since it covers many lines and uses exceptions for control flow. Introducing the `next?` method makes enumerators a little nicer to work with. A patch with an example implementation for ruby trunk is attached (in git-diff format, any feedback welcome). I agree that my patch will be licensed under the Ruby License. ---Files-------------------------------- enumerator_next.diff (2.26 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: