object

optional

Constructors for optional term references. An optional reference represents a term that may or may not be present. Optional references should be regarded as opaque terms and always used with the "optional(_)" object by passing the reference as a parameter.

author:
Paulo Moura
version:
1.2
date:
2017/8/8
compilation flags:
static, context_switching_calls
provides:
type::type/1
type::check/2

Public interface

empty/1

Constructs an empty optional reference.

compilation flags:
static
template:
empty(Reference)
mode – number of proofs:
empty(--nonvar) – one

of/2

Constructs an optional reference from a term.

compilation flags:
static
template:
of(Term,Reference)
mode – number of proofs:
of(@term,--nonvar) – one

Protected interface

(see related entities)

Private predicates

(see related entities)

Operators

(none)

Remarks

Type-checking support
This object also defines a type "optional" for use with the "type" library object.

See also