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

Public interface

empty/1

Constructs an empty optional reference.

Compilation flags:
static
Template:
empty(Reference)
Mode and number of proofs:
empty(--nonvar) - one

of/2

Constructs an optional reference from a term.

Compilation flags:
static
Template:
of(Term,Reference)
Mode and 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.