This module provides compatibility to YAP through the directive expects_dialect/1:

:- expects_dialect(yap)

The task of this module is:

• Implement system predicates available in YAP we do not yet or do not wish to support in SWI-Prolog. Export these predicates.
• Provide yap_<name>(...) predicates for predicates that exist both in YAP and SWI-Prolog and define goal_expansion/2 rules to map calls to these predicates to the yap_<name> version. Export these predicates.
• Alter the library search path, placing dialect/yap before the system libraries.
• Allow for .yap extension as extension for Prolog files. If both a .pl and .yap is present, the .yap file is loaded if the current environment expects YAP.

Current set is taken from http://www.david-reitter.com/compling/prolog/compat_swi.pl, written by David Reitter and Steve Moyle

author

- Jan Wielemaker

To be done

- Fill it in!

 yap_expansion(+In, +Out)[multifile]

goal_expansion rules to emulate YAP behaviour in SWI-Prolog. The expansions below maintain optimization from compilation. Defining them as predicates would loose compilation.

 gc

Garbage collect.

Compatibility

- yap

 depth_bound_call(:Goal, :Limit)

Equivalent to call_with_depth_limit(Goal, Limit, _Reached)

Compatibility

- yap

 system(+Command)

Equivalent to shell(Command).

Compatibility

- yap

 exists(+File)

Equivalent to exists_file(File).

Compatibility

- yap

 assert_static(:Term)

Assert as static predicate. SWI-Prolog provides compile_predicates/1 to achieve this. The emulation is a mere alias for assert/1, as immediate compilation would prohibit further calls to this predicate.

deprecated

- Use assert/1 and compile_predicates/1 after completing the predicate definition.

Compatibility

- yap

 source is det

YAP directive to maintain source-information. We have that always.

 yap_flag(+Key, +Value) is det

Map some YAP flags to SWI-Prolog. Supported flags:

write_strings:Bool

If on, writes strings as "..." instead of a list of integers. In SWI-Prolog this only affects write routines that use portray.

 yap_style_check(+Style) is det

Map YAP style-check options onto the SWI-Prolog ones.