``hook_flows``
==============

The ``hook_pipeline`` and ``hook_set`` parametric objects in this
library implement common scenarios of combining multiple hook objects
for the expansion of source files.

API documentation
-----------------

Open the
`../../docs/library_index.html#hook_flows <../../docs/library_index.html#hook_flows>`__
link in a web browser.

Loading
-------

To load all entities in this library, load the ``loader.lgt`` file:

::

   | ?- logtalk_load(hook_flows(loader)).

Testing
-------

To test this library predicates, load the ``tester.lgt`` file:

::

   | ?- logtalk_load(hook_flows(tester)).

Usage
-----

Pre-processing a source file with a hook object can be accomplished by
either compiling the source file using the option ``hook(HookObject)``
or by adding to the top of the file the directive:

::

   :- set_logtalk_flag(hook, HookObject).

Note that ``set_logtalk_flag/2`` directives are local to a source file.

The ``hook_pipeline(Pipeline)`` is a parametric object where the
parameter is a list of hook objects, interpreted as a pre-processing
pipeline: the results of a hook object are passed to the next hook
object.

The ``hook_set(Set)`` is a parametric object where the parameter is a
list of hook objects, interpreted as a set of hook object: hooks in the
set are tried until one of them succeeds.

Note that these two basic hook flows can be freely combined and also
used as examples of how to construct custom hook flows.
