From: Rodrigo Rosenfeld Rosas <rr.rosas@...>
Date: 2011-06-06T20:16:10+09:00
Subject: [ruby-core:36782] [Ruby 1.9 - Feature #4830] Provide Default Variables for Array#each and other iterators


Issue #4830 has been updated by Rodrigo Rosenfeld Rosas.


I'm not saying we should copy Groovy syntax or ideas. I'm just showing that this is already done in Groovy.

At first I liked the idea of not needing to define an internal variable, but as I started to use it, I run into trouble where it was a bit difficult to figure out what was going wrong on in cases like this:

someCollection.each {
   doSomeOperationWith(it)
   Thread.start { println it } // "it" here is not an item from the collection
}
----------------------------------------
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.


-- 
http://redmine.ruby-lang.org