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# -(+Number, -Result)

Unifies the negative of Number 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 the negative of 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

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