From: Lazaridis Ilias <ilias@...>
Date: 2011-06-09T19:54:17+09:00
Subject: [ruby-core:36886] [Ruby 1.9 - Feature #4830] Provide Default Variables for Array#each and other iterators


Issue #4830 has been updated by Lazaridis Ilias.


Charles Nutter wrote:
[...]
> FWIW, I have implemented "it" in JRuby previously, just for fun. It's not hard to add, if the powers decide it's a good feature for Ruby.

Some important details:

* the user can choose to use explicit variables. 
* existent code behaves exactly the same
* only if existent code is changed to use defaults, care must be take to not shadow local variables (should be very rare that an "accident" happens)
* a user can decide to write only new code with defaults
----------------------------------------
Feature #4830: Provide Default Variables for Array#each and other iterators
http://redmine.ruby-lang.org/issues/4830

Author: Lazaridis Ilias
Status: Assigned
Priority: Low
Assignee: Yukihiro Matsumoto
Category: core
Target version: 


for arrays: use "item" by default
for hashes: use "key" and "value" by default

names = ["Jane", "Michele", "Isabella"]
names.each { |name| print name, "\n" } 
names.each { print item, "\n" } 

contact = {name:"Jane", phone:"1234567"}
contact.each { |key, value| print key, ": ", value, "\n"}
contact.each { print key, ": ", value, "\n"}

-

The benefits are:

* more compact code (without loosing clarity of the code).
* no repetitions ("names, name, name") in a one-liner with {} block

This extension does not break any existent behaviour.


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