my %lookingFor;
my $ref = [1, 2, 3];
$lookingFor{qr/a.*blah/o} = $ref;
$lookingFor{qr/the.*blee/o} = $ref;

#Tie::RegexpHash would let you do $lookingFor{$bigfileline}
#without looping over keys() at all.  No idea if it's faster.