It isn't the cause of the particular error message you mention, but the last character in your example is wrong. - It should be a round bracket, not curvy.

foreach $k(sort {$match{$a}<=>$match{$b}} keys %match}
                                                     ^
foreach $k(sort {$match{$a}<=>$match{$b}} keys %match) { }
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It's good to copy-and-paste code examples so that you don't introduce other errors in the re-typing.