12.4.15 Foreign Code and Modules

Modules are identified via a unique handle. The following functions are available to query and manipulate modules.

module_t PL_context()

Return the module identifier of the context module of the currently active foreign predicate. If there is no currently active predicate it returns a handle to the user module.

bool PL_strip_module(term_t +raw, module_t *m, term_t -plain)

Utility function. If raw is a term, possibly holding the module construct <module>:<rest>, this function will make plain a reference to <rest> and fill module * with <module>. For further nested module constructs the innermost module is returned via module *. If raw is not a module construct, raw will simply be put in plain. The value pointed to by m must be initialized before calling PL_strip_module(), either to the default module or to NULL. A NULL value is replaced by the current context module if raw carries no module. The following example shows how to obtain the plain term and module if the default module is the user module:

{ module m = PL_new_module(PL_new_atom("user"));
  term_t plain = PL_new_term_ref();

  PL_strip_module(term, &m, plain);
  ...
}

Returns TRUE on success and FALSE on error, leaving an exception. Currently the only exception condition is raw to be a cyclic term.

atom_t PL_module_name(module_t module)

Return the name of module as an atom.

module_t PL_new_module(atom_t name)

Find an existing module or create a new module with the name name. Currently aborts the process with a fatal error on failure. Future versions may raise a resource exception and return (module_t)0.