From: Suraj Kurapati <sunaku@...>
Date: 2011-10-05T02:50:05+09:00
Subject: [ruby-core:39945] [Ruby 1.9 - Bug #5406][Open] inconsistent odd-length array rejection in Hash[*ary] vs Hash[ary]


Issue #5406 has been reported by Suraj Kurapati.

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Bug #5406: inconsistent odd-length array rejection in Hash[*ary] vs Hash[ary]
http://redmine.ruby-lang.org/issues/5406

Author: Suraj Kurapati
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 1.9.x
ruby -v: ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-linux]


Hello,

Hash[*ary] raises an error when given odd number of arguments:

>> Hash.[]( 1, 2, 3 )
ArgumentError: odd number of arguments for Hash
	from (irb):3:in `[]'
	from (irb):3
	from /usr/bin/irb:12:in `<main>'

In contrast, Hash[ary] silently accepts odd-length arrays:

>> Hash.[](  [1, 2, 3]  )
{}
>> Hash.[](  [[1, 2], 3]  )
{
    1 => 2
}
>> Hash.[](  [[1, 2], [3]]  )
{
    1 => 2,
    3 => nil
}
>> Hash.[](  [[1, 2], [3,4,5]]  )
{
    1 => 2
}

I think this behavior is inconsistent.  Please either:

(1) change Hash[ary] to raise errors upon seeing odd-length arrays or 

(2) change Hash[*ary] to not raise an error for odd number of arguments and instead accept the last odd argument as a key with value nil, just like this existing behavior:

>> Hash.[](  [[1, 2], [3]]  )
{
    1 => 2,
    3 => nil
}

Thanks for your consideration.


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