[ Arithmetic | Reference Manual | Alphabetic Index ]

+(+Number, -Result)

-Result is + +Number

Checks if Number is a number and unifies it with Result.
Number
A number.
Result
Output: a number.

Description

Result is identical to Number.

This predicate can be used as a function in arithmetic expressions. In coroutining mode, if Number is uninstantiated, the call to +/2 is delayed until this variable is instantiated.

Modes and Determinism

Exceptions

(4) instantiation fault
Number is not instantiated (non-coroutining mode only).
(24) number expected
Number is not of a numeric type.

Examples

Success:
    Result is + 1.		% gives Result = 1
    Result is + 5.        	% gives Result = 5
    Result is + -6.2.     	% gives Result = -6.2

    Result is +(1).		% gives Result = 1
    Result is +(5).        	% gives Result = 5
    Result is +(-6.2).     	% gives Result = -6.2

See Also

is / 2