SWI-Prolog has a mechanism for easy incorporation of community
extensions. See the pack
landing page for details and available packs. This section documents
the built-in predicates to attach packs. Predicates for creating,
registering and installing packs are provided by the library
library(prolog_pack).
- attach_packs
- Attaches all packs in subdirectories of directories that are accessible
through the file search path (see absolute_file_name/3)
pack. The default for this search path is given below. See
file_search_path/2
for the app_data search path.
user:file_search_path(pack, app_data(pack)).
The predicate attach_packs/0
is called on startup of SWI-Prolog.
- attach_packs(+Directory)
- Attach all packs in subdirectories of Directory. Same as
attach_packs(Directory,[]).
- attach_packs(+Directory,
+Options)
- Attach all packs in subdirectories of Directory. Options is
one of:
- search(+Where)
- Determines the order in which pack library directories are searched.
Default is to add new packages at the end (
last). Using
first, new packages are added at the start.
- duplicate(+Action)
- Determines what happens if a pack with the same name is already
attached. Default is
warning, which prints a warning and
ignores the new pack. Other options are keep, which is like warning
but operates silently and replace, which detaches the old
pack and attaches the new.
The predicate attach_packs/2
can be used to attach packages that are bundled with an application.
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