Result is rationalize(Number)
    which should be preferred.
When Number is an integer, Result is a rational with denominator 1.
When Number is already a rational, Result is identical to Number.
When Number is a float, Result is a rational whose value approximates the value of the float to the accuracy of the float representation. rationalize/2 usually produces more compact rationals that rational/2. Both rationalize/2 and rational/2 produce results that convert back into the original float. rational/2 is usually faster than rationalize/2.
Bounded reals cannot be converted to rationals.
In coroutining mode, if Number is uninstantiated, the call to rationalize/2 is delayed until this variable is instantiated.
Success:
    Result is rationalize(25).		% gives Result = 25_1
    Result is rationalize(1.5).		% gives Result = 3_2
    Result is rationalize(3_4).		% gives Result = 3_4
    Result is rationalize(9_12).	% gives Result = 3_4
    Result is rationalize(-6).		% gives Result = -6_1
    Result is rationalize(0.1).		% gives Result = 1_10
Error:
    Result is rationalize(0.9__1.1).	% unimplemented