[ Arithmetic | Reference Manual | Alphabetic Index ]
# +(+Number, -Result)

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

## Description

This predicate is used by the ECLiPSe compiler to expand evaluable
arithmetic expressions. So the call to +(Number, Result) is equivalent
to
Result is +Number

which should be preferred for portability.
Result is identical to Number.

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