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yap-6.3/library/hacks.yap
2019-02-17 23:19:26 +00:00

99 lines
2.4 KiB
Prolog

/**
* @file library/hacks.yap
* @author VITOR SANTOS COSTA <vsc@VITORs-MBP.lan>
* @date Tue Nov 17 19:00:25 2015
*
* @brief Prolog hacking
*
*
*/
:- module(yap_hacks, [
current_choicepoint/1,
parent_choicepoint/1,
parent_choicepoint/2,
cut_by/1,
cut_at/1,
current_choicepoints/1,
choicepoint/7,
current_continuations/1,
continuation/4,
stack_dump/0,
stack_dump/1,
enable_interrupts/0,
disable_interrupts/0,
virtual_alarm/3,
fully_strip_module/3,
context_variables/1
]).
/**
* @addtogroup Hacks
* @{
* @brief Manipulate the Prolog stacks, including setting and resetting
* choice-points.
*
**/
/**
* @pred stack_dump
*
* Write the current ancestor stack to the outout. Ancestors may have:
* - terminated
* - still have sub-goals to execute, if so, they left an _environment_
* - still have clauses they may nacktrack to; if so, they left a _choice point_
*
*/
stack_dump :-
stack_dump(-1).
/**
* @pred stack_dump(+N)
*
* Report the last _N_ entries in the stack (see stack_dump/0)
*/
stack_dump(Max) :-
current_choicepoints(CPs),
current_continuations([Env|Envs]),
continuation(Env,_,ContP,_),
length(CPs, LCPs),
length(Envs, LEnvs),
format(user_error,'~n~n~tStack Dump~t~40+~n~nAddress~tChoiceP~16+ Cur/Next Clause Goal~n',[LCPs,LEnvs]),
'$hacks':display_stack_info(CPs, Envs, Max, ContP, StackInfo, []),
run_formats(StackInfo, user_error).
run_formats([], _).
run_formats([Com-Args|StackInfo], Stream) :-
format(Stream, Com, Args),
run_formats(StackInfo, user_error).
/**
* @pred virtual_alarm(+Interval, 0:Goal, -Left)
*
* Activate an alarm to execute _Goal_ in _Interval_ seconds. If the alarm was active,
* bind _Left_ to the previous value.
*
* If _Interval_ is 0, disable the current alarm.
*/
virtual_alarm(Interval, Goal, Left) :-
Interval == 0, !,
virtual_alarm(0, 0, Left0, _),
on_signal(sig_vtalarm, _, Goal),
Left = Left0.
virtual_alarm(Interval, Goal, Left) :-
integer(Interval), !,
on_signal(sig_vtalarm, _, Goal),
virtual_alarm(Interval, 0, Left, _).
virtual_alarm(Interval.USecs, Goal, Left.LUSecs) :-
on_signal(sig_vtalarm, _, Goal),
virtual_alarm(Interval, USecs, Left, LUSecs).
fully_strip_module(T,M,S) :-
'$hacks':fully_strip_module(T,M,S).
%% @}