Did you know ... Search Documentation:
Predicate goal_expansion/2
Sourcegoal_expansion(+Goal1, -Goal2)
Like term_expansion/2, goal_expansion/2 provides for macro expansion of Prolog source code. Between expand_term/2 and the actual compilation, the body of clauses analysed and the goals are handed to expand_goal/2, which uses the goal_expansion/2 hook to do user-defined expansion.

The predicate goal_expansion/2 is first called in the module that is being compiled, and then follows the module inheritance path as defined by default_module/2, i.e., by default user and system. If Goal is of the form Module:Goal where Module is instantiated, goal_expansion/2 is called on Goal using rules from module Module followed by default modules for Module.

Only goals appearing in the body of clauses when reading a source file are expanded using this mechanism, and only if they appear literally in the clause, or as an argument to a defined meta-predicate that is annotated using‘0’(see meta_predicate/1). Other cases need a real predicate definition.

The expansion hook can use prolog_load_context/2 to obtain information about the context in which the goal is expanded such as the module, variable names or the encapsulating term.

Tags are associated to your profile if you are logged in
Tags: