In role Rational§
See primary documentation in context for method isNaN
method isNaN(Rational:D: --> Bool:D)
Tests whether the invocant's Num value is a NaN, an acronym for Not available Number. That is both its numerator and denominator are zero.
In Complex§
See primary documentation in context for method isNaN
method isNaN(Complex:D: --> Bool:D)
Returns true if the real or imaginary part is NaN (not a number).
say (NaN+5i).isNaN; # OUTPUT: «True» say (7+5i).isNaN; # OUTPUT: «False»