It'd be easier if you reply to my message, so I don't have to search for a response. ;)

Anyway, this code works for me:

#!/usr/bin/perl -w

use strict;

sub someFunc {
  my $args = [
    { client_number => 1, MM => 2, DD => 3, S => 4, },
  ];
  for (keys %$args) {
    my $idx = $args->[0]{$_} - 1;
    if (defined $_[$idx]) { $args->{$_} = $_[$idx], next }
    die "$_ not defined";
  }
  print "@$args\n";
}

someFunc(1,2,3,4);  # fine
someFunc(1,2,3);    # 'S' is not defined
[download]

It works under strict.

japhy -- Perl and Regex Hacker