tests/preamble.mfp

   1 $ ifxr 0 x y = x y;
   2 & ifxr 0 x y = y x;
   3 == ifxl 7 x y = eq x y;
   4 * ifxl 7 x y = mul x y;
   5 - ifxl 6 x y = sub x y;
   6 + ifxl 6 x y = add x y;
   7 fac i = if (i == 0) 1 $ i * fac (i - 1);
   8 start = fac 5;