The bound to be a simple explanation for this phenomena, but if there is, I cannot see it?

I was trying to use my uniq() utility routine, which has seen service in it's present form for months, if not years, and it suddenly stopped working. It gave no visible errors or warnings, it simply failed to do anything.

After scratching my head most of last night, I gave up. Today, I realised that the key to the failure was the fact that I was

  • chaining it with sort.
  • and that I was using the implicit default comparator block.

    What am I doing wrong? 

    #! perl -slw
use strict;

sub uniq { my %x; @x{@_} = (); keys %x }

my @array = ( 'A' .. 'Z', reverse 'A' .. 'Z' );

## Explicit sort block works as expected
print sort { $a cmp $b } uniq @array;

## implicit sort block "disables"!? the uniq() sub?
print sort uniq @array;

__DATA__
P:\test>junk
ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZZYXWVUTSRQPONMLKJIHGFEDCBA

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    In reply to implicit sort disables a chained subroutine? by BrowserUk

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