Enter functional programming techniques.
sub by_hashval_func {
my ( $hashref ) = @_;
return sub { $hashref->{ $a } cmp $hashref->{ $b } };
}
foreach my $key ( sort by_hashval_func( \%hash ) keys %hash ) {
# do something useful
}
Update: I just remembered that $a and $b are package globals, ie the above will not work if by_hashval_func is in a different package than the sort call ultimately using the closure. To cater to that case, the prototyped sort block form is necessary:
sub by_hashval_func {
my ( $hashref ) = @_;
return sub($$) { $hashref->{ $_[0] } cmp $hashref->{ $_[1] } };
}
Makeshifts last the longest.
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