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Call goals with reified (exit) ports.
Author(s): Jose F. Morales.
Predicates to delay the execution of the (exit) port of a goal. This is useful to introduce side-effects at selected points (e.g., clean-ups before goal exit in failure or exception conditions).
Usage and interface
- Library usage:
:- use_module(library(port_reify)). - Exports:
- Predicates:
once_port_reify/2, port_call/1. - Regular Types:
exit_port/1.
- Predicates:
Documentation on exports
REGTYPEexit_port/1
exit_port(Result)
Exit port of a goal execution, defined as:
- success: goal succeeded
- failure: goal failed
- exception(E): goal threw an exception E
PREDICATEonce_port_reify/2
Usage:once_port_reify(Goal,Result)
Execute once(Goal) (alternatives are cut) and obtain its execution port Port, which can be continued with port_call/1.
The sequence (once_port_reify(Goal,P),Cleanup,port_call(P)) is semantically equivalent to once(Goal), but executes Cleanup goals in case of success, failure, and exception.
- The following properties should hold upon exit:
(port_reify:exit_port/1)port_reify:exit_port(Result)
PREDICATEport_call/1
Usage:port_call(Result)
Succeed, fail, or throw the exception from Result (see once_port_reify/2).
- The following properties should hold at call time:
(port_reify:exit_port/1)port_reify:exit_port(Result)
Documentation on imports
This module has the following direct dependencies:- Packages:
prelude, initial, condcomp, assertions, assertions/assertions_basic, regtypes, isomodes, hiord.