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 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.
When using a backend Prolog compiler that supports modules, it’s also possible to use as parameter a list of hook modules as long as their names do not coincide with the names of loaded objects.