From: "Haase, Konstantin" <Konstantin.Haase@...>
Date: 2011-11-01T09:32:59+09:00
Subject: [ruby-core:40589] Re: [ruby-trunk - Feature #5531][Open] deep_value for dealing with nested hashes

What's the difference (usability wise) between

	hash[:foo][:bar]

and

	hash.dv(:foo, :bar)

Konstantin

On Oct 31, 2011, at 16:52 , Kyle Peyton wrote:

> 
> Issue #5531 has been reported by Kyle Peyton.
> 
> ----------------------------------------
> Feature #5531: deep_value for dealing with nested hashes
> http://redmine.ruby-lang.org/issues/5531
> 
> Author: Kyle Peyton
> Status: Open
> Priority: Normal
> Assignee: 
> Category: 
> Target version: 
> 
> 
> This feature request stems from dealing with nested hashes, like the params from a request often dealt with in web frameworks.
> 
> Conditional code often needs to be written with multiple logical ANDs in order to achieve what this simple function can:
> 
> class Hash
>  def deep_value(*ks)
>    if ks.size == 1
>      return self[ks.shift]
>    else
>      val = ks.shift
>      return (self[val].is_a?(Hash) ? self[val].deep_value(*ks) : nil)
>    end
>  end
> 
>  alias dv deep_value
> end
> 
> 
> deep_value (dv) will simply recurse over a hash given a set of indexes and return the value at the end.
> 
> Example:
> 
>> foo = {:bar => {:baz => 'blah'}}
>> foo.dv(:bar, :baz)
> -> 'blah'
>> foo.dv(:cats)
> -> nil
> 
> 
> 
> -- 
> http://redmine.ruby-lang.org
>