#!/usr/bin/perl -w 

use strict;

sub do_this_cool_function {
  my %args = (
        -retire     => "never",
        -pizza     => "cheese",
        -payscale   => 0,
        -beer      => "guiness",
        @_,         # argument pair list goes here
    );

    print "I wanna retire $args{-retire} if my pizza is $args{-pizza}.
+\n";
}

do_this_cool_function(-retire=>'early', -payscale=>-55.00, -pizza=>'co
+ld', -beer=>'none');

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Bareword "none" not allowed while "strict subs" in use at ./test.pl li
+ne 17.
Unquoted string "none" may clash with future reserved word at ./test.p
+l line 17.
Execution of ./test.pl aborted due to compilation errors.
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No, this is proper syntax: do_this_cool_function (-retire=>'early', -payscale=>-55.00, -pizza=>'cold', -beer=>none); This should work fine as in many modules like CGI.pm. The leading '-' in -retire will perl to interpret '-retire' as a string. Here is a snip from perlop

       Unary "-" performs arithmetic negation if the operand is
       numeric.  If the operand is an identifier, a string
       consisting of a minus sign concatenated with the
       identifier is returned.  Otherwise, if the string starts
       with a plus or minus, a string starting with the opposite
       sign is returned.  One effect of these rules is that
       -bareword is equivalent to "-bareword".
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Which is why -beer isn't a bareword. But the => is equivalent to a , (comma) thus ending the bareword, er string. So then
    -beer, none
will result in none being a bareword. At least, that's how I understand it.