From: Rodrigo Rosenfeld Rosas <rr.rosas@...>
Date: 2012-02-15T00:31:15+09:00
Subject: [ruby-core:42630] [ruby-trunk - Feature #6023][Open] Add "a ?= 2" support for meaning "a = a.nil? ? 2 : a"


Issue #6023 has been reported by Rodrigo Rosenfeld Rosas.

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Feature #6023: Add "a ?= 2" support for meaning "a = a.nil? ? 2 : a"
https://bugs.ruby-lang.org/issues/6023

Author: Rodrigo Rosenfeld Rosas
Status: Open
Priority: Normal
Assignee: Yukihiro Matsumoto
Category: core
Target version: 2.0.0


I've just proposed this idea to Groovy and I thought the same semantics would be interesting to have in Ruby too:

http://jira.codehaus.org/browse/GROOVY-5306

This is a minor, but important, difference to the "a ||= 2" syntax.

This would be a caching/memoization operator, and it would allow code like this:

a = nil
a ?= false # a is false now
a ?= true  # a is still false

This contrasts with

a = nil
a ||= false # a is false now
a ||= true  # a is true now



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