Logtalk reference manual
Built-in method: \+/1
\+/1
Description
\+ Goal
Not-provable meta-predicate. True iff call(Goal)
is false. This built-in meta-predicate cannot be used as a message to an object.
Template and modes
\+ +callable
Errors
- Goal is a variable:
instantiation_error
- Goal is neither a variable nor a callable term:
type_error(callable, Goal)
Examples
- Not-provable goal in the context of the object or category containing the call:
\+ Goal
- Not-provable goal sent as a message to self:
\+ ::Goal
- Not-provable goal sent as a message to an explicit object:
\+ Object::Goal
See also
call/1-N
, ignore/1
, once/1