Squares

• For example, suppose you have written a function to calculate squares

        sub square_a {
          my $x = shift;
          return $x * $x;
        }

• The guy in the next cubicle wrote one too:

        # VALUES OF BEETA GIVE RISE TO DOM
        sub square_b {
          my $fOOooO = shift() + 1;
          return exp(2*log($fOOooO)) - ($fOOooO - 1) - $fOOooO;
        }

• Is it correct?

• It passes all the tests, but that doesn't prove anything

• Let's write a function that examines the source code of another function

  • And returns true if and only if the code is for calculating squares!