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Checks if Number is a number and unifies it with Result.
- A number.
- A variable or a number.
This predicate is used by the ECLiPSe compiler to expand evaluable
arithmetic expressions. So the call to +(Number, Result) is equivalent
Result is +Number
which should be preferred for portability.
Number and Result have to be of the same type.
In coroutining mode, if Number is uninstantiated, the call to +/2 is
delayed until this variable is instantiated.
Modes and Determinism
- (4) instantiation fault
- Number is not instantiated (non-coroutining mode only).
- (24) number expected
- Number is not of a numeric type.
+(5, Result). (gives Result = 5)
+(-6.2, Result). (gives Result = -6.2)
+(A, 6). (Error 4).
+(4 + 2, 6). (Error 24).
is / 2