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# rational(?Rational)

Succeeds if Rational is a rational number.

Rational
  Prolog term.

## Description

Used to test whether Rational is a rational number.

### Modes and Determinism

- rational(?) is semidet

### Fail Conditions

Fails if Rational is not a rational number

## Examples

       Success:
       rational(1_3).
       set_flag(prefer_rationals, on), X is 1/3, rational(X).
       Fail:
       rational(1).
       rational(1.0).
       rational('1.0').
       rational(a).
       rational(X).

## See Also

atomic / 1, integer / 1, number / 1, float / 1, real / 1, breal / 1