prolog_autoload.pl -- Autoload all dependencies

The autoloader is there to smoothen program development. It liberates the programmer from finding the library that defines some particular predicate and including the proper use_module/1,2 directive in the sources. This is even better at the toplevel, where just using maplist/3 is way more comfortable than first having to load library(apply). In addition, it reduces the startup time of applications by only loading the necessary bits.

Of course, there is also a price. One is that it becomes less obvious from where some predicate is loaded and thus whether you have the right definition. The second issue is that it is harder to create a stand-alone executable because this executable, without access to the development system, can no longer rely on autoloading. Finally, program analysis becomes harder because the program may be incomplete.

This library provides autoload/0 and autoload/1 to autoload all predicates that are referenced by the program. Now, this is not possible in Prolog because the language allows for constructing arbitrary goals and runtime and calling them (e.g., read(X), call(X)).

The implementation relies on code analysis of the bodies of all clauses and all initialization goals.

 autoload is det

 autoload(+Options) is det

Force all necessary autoloading to be done now. Options:

verbose(+Boolean)

If true (default false), report on the files loaded.

undefined(+Action)

Action defines what happens if the analysis finds a definitely undefined predicate. One of ignore or error. Default is ignore.

 autoload_step(-NewFiles, -NewPreds, +Options) is det[private]

Scan through the program and autoload all undefined referenced predicates.

Arguments:

NewFiles	- is unified to the number of files loaded
NewPreds	- is unified to the number of predicates imported using the autoloader.

 walk_options(+AutoloadOptions, -WalkOptions) is det[private]

Construct the option list for the code walker. If we see an undefined predicate, we must collect these rather than printing them or immediately terminating with an exception. This reuses code from library(check).

 report_undefined(+Undefined) is det[private]

 autoload is det

 autoload(+Options) is det

Force all necessary autoloading to be done now. Options:

verbose(+Boolean)

If true (default false), report on the files loaded.

undefined(+Action)

Action defines what happens if the analysis finds a definitely undefined predicate. One of ignore or error. Default is ignore.