Module "engine"

 Jan Burse, created Aug 17. 2019 
/**


 * Some interpreter state can be queried and updated. The predicate


 * current_prolog_flag/2 allows accessing an interpreter attribute. The


 * predicate set_prolog_flag/2 allows updating an interpreter attribute.


 * The predicates halt/[0,1] allow exiting the current process.


 *


 * The predicates begin_module/1 and end_module/0 can be used to open


 * respectively close a local module. For a consulted file the predicate


 * begin_module/1 will also do first a clear of the local module, and


 * the predicate end_module/0 will do a style check of the local module.


 *


 * Warranty & Liability


 * To the extent permitted by applicable law and unless explicitly


 * otherwise agreed upon, XLOG Technologies GmbH makes no warranties


 * regarding the provided information. XLOG Technologies GmbH assumes


 * no liability that any problems might be solved with the information


 * provided by XLOG Technologies GmbH.


 *


 * Rights & License


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 * and patent rights in particular - are the sole property of XLOG


 * Technologies GmbH. If the company was not the originator of some


 * excerpts, XLOG Technologies GmbH has at least obtained the right to


 * reproduce, change and translate the information.


 *


 * Reproduction is restricted to the whole unaltered document. Reproduction


 * of the information is only allowed for non-commercial uses. Selling,


 * giving away or letting of the execution of the library is prohibited.


 * The library can be distributed as part of your applications and libraries


 * for execution provided this comment remains unchanged.


 *


 * Restrictions


 * Only to be distributed with programs that add significant and primary


 * functionality to the library. Not to be distributed with additional


 * software intended to replace any components of the library.


 *


 * Trademarks


 * Jekejeke is a registered trademark of XLOG Technologies GmbH.


 */




:- use_package(foreign(jekpro/reference/bootload)).


:- use_package(foreign(jekpro/tools/call)).


:- use_package(foreign(jekpro/tools/term)).




:- module(user, []).


:- use_module(library(stream/console)).




/**


 * current_prolog_flag(F, V): [ISO 8.17.2]


 * The predicate succeeds for the value V of the flag F.


 */


% current_prolog_flag(-Atom, -Term)


:- public current_prolog_flag/2.


current_prolog_flag(Flag, Value) :- var(Flag), !,


   sys_current_flag(Flag),


   sys_get_flag(Flag, Value).


current_prolog_flag(Flag, Value) :-


   sys_get_flag(Flag, Value).




:- private sys_current_flag/1.


:- foreign(sys_current_flag/1, 'ForeignEngine',


      sysCurrentFlag('Interpreter', 'CallOut')).




:- private sys_get_flag/2.


:- foreign(sys_get_flag/2, 'ForeignEngine',


      sysGetFlag('Interpreter', 'String')).




/**


 * set_prolog_flag(F, V): [ISO]


 * The predicate sets the flag F to the value V.


 */


% set_prolog_flag(+Atom, +Term)


:- public set_prolog_flag/2.


:- foreign(set_prolog_flag/2, 'ForeignEngine',


      sysSetFlag('Interpreter', 'String', 'Object')).




/**


 * halt: [ISO 8.17.3]


 * halt(N): [ISO 8.17.4]


 * The predicate without arguments terminates the interpreter with


 * exit value zero. The unary predicate terminates the interpreter


 * with exit value N.


 */


% halt


:- public halt/0.


halt :- halt(0).




% halt(+Integer)


:- public halt/1.


:- foreign(halt/1, 'ForeignEngine', sysHalt('Integer')).




/********************************************************/


/* Prolog Data                                          */


/********************************************************/




/**


 * welcome:


 * version:


 * The predicate displays a version banner.


 */


% welcome


:- public welcome/0.


welcome :- version.


:- set_predicate_property(welcome/0, sys_notrace).




:- public version/0.


version :-


   sys_prolog_version(V),


   write(V), nl,


   sys_prolog_vendor(W),


   write(W), nl.


:- set_predicate_property(version/0, sys_notrace).




:- private sys_prolog_version/1.


:- foreign(sys_prolog_version/1, 'ForeignEngine',


      sysPrologVersion('Interpreter')).




:- private sys_prolog_vendor/1.


:- foreign(sys_prolog_vendor/1, 'ForeignEngine',


      sysPrologVendor('Interpreter')).




/********************************************************/


/* Locale Modules                                       */


/********************************************************/




/**


 * begin_module(N):


 * The predicate begins a new typein module N.


 */


% begin_module(+Atom)


:- public begin_module/1.


begin_module(N) :-


   absolute_file_name(verbatim(N), D),


   sys_module_action(D, [action(begin_module), sys_link(sys_auto_load)]),


   set_prolog_flag(sys_last_pred, null).




/**


 * end_module:


 * The predicate ends the current typein module.


 */


% end_module


:- public end_module/0.


end_module :-


   sys_peek_stack(D),


   sys_module_action(D, [action(end_module), sys_link(sys_auto_load)]),


   set_prolog_flag(sys_last_pred, null).




/**


 * end_all_modules:


 * The predicates ends all current typein modules.


 */


% end_all_modules


:- public end_all_modules/0.


end_all_modules :-


   sys_count_stack(C), >=(C, 2), !,


   end_module,


   end_all_modules.


end_all_modules.




/**


 * top_module(M):


 * The predicate succeeds in M with the top module.


 */


:- public top_module/1.


top_module(N) :-


   sys_peek_stack(D),


   absolute_file_name(verbatim(N), D).




:- private sys_module_action/2.


:- foreign(sys_module_action/2, 'ForeignEngine',


      sysModuleAction('Interpreter', 'TermAtomic', 'Object')).




:- private sys_peek_stack/1.


:- foreign(sys_peek_stack/1, 'ForeignEngine',


      sysPeekStack('Interpreter')).




:- private sys_count_stack/1.


:- foreign(sys_count_stack/1, 'ForeignEngine',


      sysCountStack('Interpreter')).

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