# Do this once for efficiency.
use vars qw(%NUM_OPS %STR_OPS);
BEGIN {
   $NUM_OPS{$_} = eval "sub { \$_[0] $_ \$_[1] }"
      foreach (qw(<  <= != >= >  ==));

   $STR_OPS{$_} = eval "sub { \$_[0] $_ \$_[1] }"
      foreach (qw(lt le ne ge gt eq));
}