It can be done with one regexp. 
/^(?=.*a)(?=.*b)(?=.*c).*d/
   or die;

[download]

If you want to know the order in which they came, 

my %order;
@order{qw( a b c d )} =
      map length, /^(?=(.*?)a)(?=(.*?)b)(?=(.*?)c)(.*?)d/
   or die;

my @ordered = sort { $order{$a} <=> $order{$b} } keys %order;

[download]

This is probably slow for long strings.

Update: Actually, no need for a hash. 

my @order = map length, /^(?=(.*?)a)(?=(.*?)b)(?=(.*?)c)(.*?)d/
   or die;

my @ordered = ( qw( a b c d ) )[
   sort { $order[$a] <=> $order[$b] } 0..$#order
];

[download]

Update: Back to the practical, using multiple regexp and saving @- should be much faster. Especially if scanning for constants. 

my @unordered = qw( a b c d );

my @order;
for my $s (@unordered) {
   push @order, /\Q$s/ ? $-[0] : die;
}

my @ordered = @unordered[
   sort { $order[$a] <=> $order[$b] } 0..$#order
];

[download]

In reply to Re: How to replace greedy alternation? by ikegami
in thread How to replace greedy alternation? by adamcrussell

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