.. index:: print_goal_hook .. _print_goal_hook/0:

.. rst-class:: right

object

print_goal_hook

Use this object to easily print entity predicate goals before, after, or before and after calling them.

| Availability: | logtalk_load(hook_objects(loader))

| Author: Paulo Moura | Version: 1:0:0 | Date: 2020-03-14

| Compilation flags: | static, context_switching_calls

| Implements: | public :ref:`expanding <expanding/0>`

| Remarks:

• Usage: Mark a goal to be printed by prefixing it with an operator. Printing uses a comment message.
• To print goal before calling it: - Goal.
• To print goal after calling it: + Goal.
• To print goal before and after calling it: * Goal.
• Operators: This hook object uses the standard - and + prefix operators and also defines a global * prefix operator with the same type and priority.

| Inherited public predicates: |  :ref:expanding/0::goal_expansion/2  :ref:expanding/0::term_expansion/2  

.. contents:: :local: :backlinks: top

Public predicates

(no local declarations; see entity ancestors if any)

Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

(no local declarations; see entity ancestors if any)

Operators

(none)

.. seealso::

:ref:`backend_adapter_hook <backend_adapter_hook/0>`, :ref:`default_workflow_hook <default_workflow_hook/0>`, :ref:`grammar_rules_hook <grammar_rules_hook/0>`, :ref:`identity_hook <identity_hook/0>`, :ref:`prolog_module_hook(Module) <prolog_module_hook/1>`, :ref:`object_wrapper_hook <object_wrapper_hook/0>`, :ref:`write_to_stream_hook(Stream,Options) <write_to_stream_hook/2>`, :ref:`write_to_stream_hook(Stream) <write_to_stream_hook/1>`, :ref:`suppress_goal_hook <suppress_goal_hook/0>`