From: "Ondřej Bílka" <neleai@...>
Date: 2011-11-07T00:59:41+09:00
Subject: [ruby-core:40784] Re: [ruby-trunk - Feature #5531] deep_value for dealing with nested hashes

Do you need hash or something like multidimensional hash class that uses [], each iterates on nested...
On Sun, Nov 06, 2011 at 05:48:52PM +0900, Thomas Sawyer wrote:
> 
> Issue #5531 has been updated by Thomas Sawyer.
> 
> 
> Probably best to use #[] internally too.
> 
>     class Hash
>       def [](*keys)
>         keys.inject(self) {|container, key| value = container[key]; value ? value : return value}
>       end
>     end
> 
> @Alexey you may have a point. But I suspect it would need to be conditioned off of responding to #to_h or #to_hash instead of using `is_a?(Hash)`.
> 
> ----------------------------------------
> 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

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