[ Arithmetic | The ECLiPSe Built-In Predicates | Reference Manual | Alphabetic Index ]
# sum(+ExprList, -Result)

Evaluates the the arithmetic expressions in ExprList and unifies their sum
with Result.
*ExprList*
- A list of arithmetic expressions.
*Result*
- A variable or number.

## Description

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

which should be preferred.
In coroutining mode, if the list is only partly instantiated, the
predicate delays until the list is complete.

### Modes and Determinism

### Modules

This predicate is sensitive to its module context (tool predicate, see @/2).
### Exceptions

*(4) instantiation fault *
- ExprList is a partial list (non-coroutining mode only).
*(5) type error *
- ExprList is not a proper list.
*(5) type error *
- Result is not a number.

## Examples

Success:
X is sum([1,2,3]). % gives X = 6

## See Also

is / 2, + / 3