Compiler Pragmas

:- pragma(Option).

• debug - generate code which can be inspected with the debugger. This overrides the global setting of the debug_compile flag.

• nodebug - generate optimized code with no debugger support. This overrides the global setting of the debug_compile flag.

• silent_debug - generate code which cannot be inspected by the debugger, but which allows to debug predicates called by it. This is similar to setting the leash flag of all subgoals in the following clauses to notrace. This option is useful e.g. for library predicates which call other Prolog predicates: the user wants to see in the debugger the call to the library predicate and to the invoked predicate, but no internal calls in the library predicates.

• expand - do in-line expansion of some subgoals, like =/2, is/2 and others. This code can still be inspected with the debugger but the expanded subgoals look differently than in the normal debugged code, or their arguments cannot be seen. This pragma overrides the global setting of the goal_expansion flag.

• noexpand - inhibit the in-line goal expansion. This pragma overrides the global setting of the goal_expansion flag.

• skip - set the skip flag of all following predicates to on.

• noskip - set the skip flag of all following predicates to off.

• system - set the type flag of all following predicates to built_in. Moreover, all following predicates will have unspecified source_file and source_line flags.

The pragma is active from its specification in the file until the file end or until it is disabled by another pragma. Recursive compilations or calls to other compiling predicates are not affected by the pragma. Pragmas which have the same effect as global flags override the global flags if they specify more optimized code. For instance, the pragma debug has no effect if the global flag debug_compile is off, but the pragma nodebug overrides the global flag debug_compile being on.

The pragmas are useful mainly for libraries and other programs that should be always compiled in a particular mode independently of the global flags setting.