RationalRetractions SΒΆ

retract.spad line 51

rational number testing and retraction functions. Date Created: March 1990

rational: S -> Fraction Integer
rational(x) returns x as a rational number; error if x is not a rational number.
rational?: S -> Boolean
rational?(x) returns true if x is a rational number, false otherwise.
rationalIfCan: S -> Union(Fraction Integer, failed)
rationalIfCan(x) returns x as a rational number, “failed” if x is not a rational number.