First of all, this task is not one that should be undertaken by a subroutine using sort(). One must remember that sort sorts into an array, so there is no knowledge of the hash we sorted from! Therefore, the task you propose is (probbably) impossiblie, as long as you want to sort by_something, without giving it the hashes name, and globalizing the hash, or just passing the hash itself (Which will come up later).

The pragmatic programmer aproaches issues that he has trouble with, with differant. I have to ask, what is the purpose of a subroutine that sorts? Why not pass the subroutine a hash, , and hard code the sort/hash name into the script. (Does exactly the same thing, except you don't have to deal with those problems....)

key_val(%whatever_hash_name_you_want_);
sub key_val {
my %hash = shift;
map {print "$_ - $hash{$_} \n";} sort{$hash{$a} cmp $hash{$b}} keys %h
+ash;
}
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Passing coderefs would even allow you to print in any format you wished!

If, for some reason you *have* to have a subroutine block in the sort: It would be more pragmatic to just use the hashname as an arg. You can then shift the hashname, and do the sort, but this would not compy with strict (you can figure the code out yourself :) )