Thanks to Quintus, Prolog adapted an extensible mechanism for
searching files using file_search_path/2.
This mechanism allows for comfortable and readable specifications.
Suppose you have extensive library packages on graph algorithms, set
operations and GUI primitives. These sub-projects are likely candidates
for re-use in future projects. A good choice is to create a directory
with sub-directories for each of these sub-projects.
Next, there are three options. One is to add the sub-projects to the
directory hierarchy of the current project. Another is to use a
completely dislocated directory. Third, the sub-project can be added to
the SWI-Prolog hierarchy. Using local installation, a typical file_search_path/2
is:
:- prolog_load_context(directory, Dir),
asserta(user:file_search_path(myapp, Dir)).
user:file_search_path(graph, myapp(graph)).
user:file_search_path(ui, myapp(ui)).
When using sub-projects in the SWI-Prolog hierarchy, one should use
the path alias swi as basis. For a system-wide
installation, use an absolute path.
Extensive sub-projects with a small well-defined API should define a
load file with calls to use_module/1
to import the various library components and export the API.
