what you want is not possible, because you can't have a single hash key retrieve both a plain scalar and a hash reference. 
my %hash;

$hash{foo} = 'bar';

# the following replaces the value of $hash{foo} with a hash reference
$hash{foo}{bar} = 'baz';

# the following is equivalent
$hash{foo} = { bar => 'baz' };

[download]
so, if someone did: builder('baz', [ 'foo', 'bar' ]); it would wipe out the effect of: builder('bar', [ 'foo' ]);

In reply to RE: RE: RE: Nesting... or something. by mdillon
in thread Nesting... or something. by Anonymous Monk

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