built-in predicate

create_protocol/3

Description

create_protocol(Identifier, Relations, Directives)

Creates a new, dynamic, protocol. This predicate is often used as a primitive to implement high-level protocol creation methods.

Note that, when opting for runtime generated protocol identifiers, it’s possible to run out of identifiers when using a backend Prolog compiler with bounded integer support. The portable solution, when creating a large number of dynamic protocols in long-running applications, is to recycle, whenever possible, the identifiers.

When using Logtalk multi-threading features, predicates calling this built-in predicate may need to be declared synchronized in order to avoid race conditions.

Modes and number of proofs

create_protocol(?protocol_identifier, @list(protocol_relation), @list(protocol_directive)) - one

Errors

Either Relations or Directives is a variable:

instantiation_error

Identifier is neither a variable nor a valid protocol identifier:

type_error(protocol_identifier, Identifier)

Identifier is already in use:

permission_error(modify, category, Identifier)

permission_error(modify, object, Identifier)

permission_error(modify, protocol, Identifier)

Relations is neither a variable nor a proper list:

type_error(list, Relations)

Repeated entity relation clause:

permission_error(repeat, entity_relation, extends/1)

Directives is neither a variable nor a proper list:

type_error(list, Directives)

Examples

| ?- create_protocol(
        logging,
        [extends(monitoring)],
        [public([log_file/1, log_on/0, log_off/0])]
     ).

See also

abolish_protocol/1, current_protocol/1, protocol_property/2, conforms_to_protocol/2-3, extends_protocol/2-3, implements_protocol/2-3