anchor.diff:       ?assertRPNFloat("1,1 tanh", {1.083923327,0.271752585})
       ].
   
  -% Powers and Logarithms
   powers_and_logarithms_tests() ->
       [
        ?assertRPNFloat("64 sqrt", 8.0),
  
positive.code:      ?assertRPNError("log10", [-1])
      ].
  
  % Rounding
  rounding_methods() ->
      [
       ?assertRPNFloat("3.4 round",  3),
  
negative.code:      ?assertRPNFloat("-0.4,-0.75", {-0.4,-0.75})
      ].
  
  addition_tests() ->
      [
       ?assertRPNFloat("1   2    +", 3),
  