130 lines
3.9 KiB
C++
130 lines
3.9 KiB
C++
#ifndef YAPQ_HH
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#define YAPQ_HH 1
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/**
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Queries and engines
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*/
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/**
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* @brief Queries
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*
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* interface to a YAP Query;
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* uses an SWI-like status info internally.
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*/
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class YAPQuery: public YAPPredicate, open_query_struct {
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Term vnames;
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YAPTerm goal;
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Term t;
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void initOpenQ();
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void initQuery( Term t );
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void initQuery( YAPTerm ts[], arity_t arity );
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public:
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/// main constructor, uses a predicate and an array of terms
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///
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/// It is given a YAPPredicate _p_ , and an array of terms that must have at least
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/// the same arity as the functor.
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YAPQuery(YAPPredicate p, YAPTerm t[]);
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/// full constructor,
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///
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/// It is given a functor, module, and an array of terms that must have at least
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/// the same arity as the functor.
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YAPQuery(YAPFunctor f, YAPTerm mod, YAPTerm t[]);
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/// functor/term constructor,
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///
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/// It is given a functor, and an array of terms that must have at least
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/// the same arity as the functor. Works within the current module.
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YAPQuery(YAPFunctor f, YAPTerm t[]);
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/// string constructor without varnames
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///
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/// It is given a string, calls the parser and obtains a Prolog term that should be a callable
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/// goal.
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inline YAPQuery(const char *s): YAPPredicate(s, t, vnames)
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{
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initQuery( t );
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};
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/// set flags for query execution, currently only for exception handling
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void setFlag(int flag) {q_flags |= flag; }
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/// reset flags for query execution, currently only for exception handling
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void resetFlag(int flag) {q_flags &= ~flag; }
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///`b first query
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///
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/// actually implemented by calling the next();
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inline bool first() { return next(); }
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/// ask for the next solution of the current query
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/// same call for every solution
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bool next();
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/// represent the top-goal
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const char *text();
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/// remove alternatives in the current search space, and finish the current query
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void cut();
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/// finish the current query: undo all bindings.
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void close();
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/// query variables.
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YAPListTerm namedVars();
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};
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// Java support
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/// This class implements a callback Prolog-side. It will be inherited by the Java or Python
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/// class that actually implements the callback.
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class YAPCallback {
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public:
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virtual ~YAPCallback() { }
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virtual void run() { LOG("callback"); }
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virtual void run(char *s) { }
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};
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/**
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* @brief YAP Engine: takes care of the execution environment
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where we can go executing goals.
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*
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*
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*/
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class YAPEngine {
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private:
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YAPCallback *_callback;
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YAP_init_args init_args;
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YAPError yerror;
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public:
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YAPEngine(char *savedState = (char *)NULL,
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size_t stackSize = 0,
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size_t trailSize = 0,
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size_t maxStackSize = 0,
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size_t maxTrailSize = 0,
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char *libDir = (char *)NULL,
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char *bootFile = (char *)NULL,
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char *goal = (char *)NULL,
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char *topLevel = (char *)NULL,
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bool script = FALSE,
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bool fastBoot = FALSE,
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YAPCallback *callback=(YAPCallback *)NULL); /// construct a new engine, including aaccess to callbacks
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/// kill engine
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~YAPEngine() { delYAPCallback(); }
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/// remove current callback
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void delYAPCallback() { _callback = 0; }
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/// set a new callback
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void setYAPCallback(YAPCallback *cb) { delYAPCallback(); _callback = cb; }
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/// execute the callback.
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////void run() { if (_callback) _callback->run(); }
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/// execute the callback with a text argument.
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void run( char *s) { if (_callback) _callback->run(s); }
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/// execute the callback with a text argument.
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YAPError hasError( ) { return yerror.get(); }
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/// build a query on the engine
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YAPQuery *query( const char *s ) {
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return new YAPQuery( s );
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};
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/// current module for the engine
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YAPModule currentModule( ) { return YAPModule( ) ; }
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/// current directory for the engine
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const char *currentDir( ) {
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char dir[1024];
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std::string s = Yap_getcwd(dir, 1024-1);
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return s.c_str();
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}
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};
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#endif /* YAPQ_HH */
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