I have studied the Lore of the Perl Monks, and found much to recommend it, but not the answer to my question. I want to combine two hashes into a third. The following works for my needs, but I would like to know if it is guaranteed to work, or merely coincidental. 
    %a = (font => 'Arial',
          size => 10,
          bold => 0);
    %b = (size => 12);

    %fmt = (%a, %b);

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I want the final hash to have (font=>'Arial',size=>12,bold=>0) so that the values in %b overwrite values in %a where necessary. I'd like to be sure that in future versions of Perl, %a won't suddenly decide to start overwriting %b. I don't think it should make a difference, but I don't actually plan to create the third hash explicitly; instead, I'll use it in a function call: 
    $object->write( 'Some Stuff', 
                    $object2->format( %a, (size => 12)) );

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My hashes are small and insignificant, yet dear to me. But because they are small I am more concerned with shortness and clarity of the code than with raw efficiency.

In reply to Simple concatenation of hashes by gholley

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