Section "magnitude"
We support predicates that compare numbers by their magnitude,
looking only at the value and not at the type. This is in contrast
to Prolog unification (=)/2 or Prolog syntactic equality (==)/2
which both take the value and the type into account, whereas
(=:=)/2 does convert integer arguments to float before comparison,
if at least one argument is float.
We provide literals 0rNaN, 0rInf and -0rInf for not a number,
positive and negative infinity respectively. These special values
are considered Prolog numbers, that are neither interger nor
float. The special values are understood by the evaluable
functions (-)/2, min/3 and max/3 and by the predicates (=:=)/2,
(<)/2, etc.. Otherwise special values cause an error.
The following magnitude evaluable functions are provided:
- abs(A, B): [ISO 9.1.7]
- The predicate succeeds in B with the absolute value of A.
- sign(A, B): [ISO 9.1.4]
- The predicate succeeds in B with the sign of A.
- min(A, B, C): [TC2 9.3.9]
- The predicate succeeds in C with the minimum of A and B.
- max(A, B, C): [TC2 9.3.8]
- The predicate succeeds in C with the maximum of A and B.
- truncate(A, B): [ISO 9.1.7]
- The predicate succeeds in B with the truncate of A.
- floor(A, B): [ISO 9.1.7]
- The predicate succeeds in B with the floor of A.
- ceiling(A, B): [ISO 9.1.7]
- The predicate succeeds in B with the ceiling of A.
- round(A, B): [ISO 9.1.7]
- The predicate succeeds in B with the rounding of A.
- inf(A):
- The predicate succeeds in A with the positive infinity.
- nan(A):
- The predicate succeeds in A with the not a number.
The following magnitude predicates are provided:
- X =:= Y: [ISO 8.7.1]
- The predicate succeeds when X number equals Y, otherwise
fails.
- X =\= Y: [ISO 8.7.1]
- The predicate succeeds when X does not number equal Y,
otherwise fails.
- X < Y: [ISO 8.7.1]
- The predicate succeeds when X is number less than Y, otherwise
fails.
- X >= Y: [ISO 8.7.1]
- The predicate succeeds when X is number greater or equal to Y,
otherwise fails.
- X > Y: [ISO 8.7.1]
- The predicate succeeds when X is number greater than Y,
otherwise fails.
- X =< Y: [ISO 8.7.1]
- The predicate succeeds when X is number less or equal to Y,
otherwise fails.