1 /********************* */
4 ** Top contributors (to current version):
5 ** Dejan Jovanovic, Morgan Deters, Tim King
6 ** This file is part of the CVC4 project.
7 ** Copyright (c) 2009-2020 by the authors listed in the file AUTHORS
8 ** in the top-level source directory) and their institutional affiliations.
9 ** All rights reserved. See the file COPYING in the top-level source
10 ** directory for licensing information.\endverbatim
12 ** \brief Base of the theory interface.
14 ** Base of the theory interface.
17 #include "cvc4_private.h"
19 #ifndef CVC4__THEORY__THEORY_H
20 #define CVC4__THEORY__THEORY_H
26 #include <unordered_set>
28 #include "context/cdhashset.h"
29 #include "context/cdlist.h"
30 #include "context/cdo.h"
31 #include "context/context.h"
32 #include "expr/node.h"
33 #include "options/options.h"
34 #include "options/theory_options.h"
35 #include "smt/command.h"
37 #include "smt/logic_request.h"
38 #include "theory/assertion.h"
39 #include "theory/care_graph.h"
40 #include "theory/decision_manager.h"
41 #include "theory/ee_setup_info.h"
42 #include "theory/logic_info.h"
43 #include "theory/output_channel.h"
44 #include "theory/theory_id.h"
45 #include "theory/theory_inference_manager.h"
46 #include "theory/theory_rewriter.h"
47 #include "theory/theory_state.h"
48 #include "theory/trust_node.h"
49 #include "theory/valuation.h"
50 #include "util/statistics_registry.h"
55 class ProofNodeManager
;
59 class QuantifiersEngine
;
61 class SubstitutionMap
;
65 class CandidateGenerator
;
66 }/* CVC4::theory::rrinst namespace */
70 }/* CVC4::theory::eq namespace */
73 * Base class for T-solvers. Abstract DPLL(T).
75 * This is essentially an interface class. The TheoryEngine has
76 * pointers to Theory. Note that only one specific Theory type (e.g.,
77 * TheoryUF) can exist per NodeManager, because of how the
78 * RegisteredAttr works. (If you need multiple instances of the same
79 * theory, you'll have to write a multiplexed theory that dispatches
82 * NOTE: A Theory has a special way of being initialized. The owner of a Theory
85 * (A) Using Theory as a standalone object, not associated with a TheoryEngine.
86 * In this case, simply call the public initialization method
87 * (Theory::finishInitStandalone).
89 * (B) TheoryEngine, which determines how the Theory acts in accordance with
90 * its theory combination policy. We require the following steps in order:
91 * (B.1) Get information about whether the theory wishes to use an equality
92 * eninge, and more specifically which equality engine notifications the Theory
93 * would like to be notified of (Theory::needsEqualityEngine).
94 * (B.2) Set the equality engine of the theory (Theory::setEqualityEngine),
95 * which we refer to as the "official equality engine" of this Theory. The
96 * equality engine passed to the theory must respect the contract(s) specified
97 * by the equality engine setup information (EeSetupInfo) returned in the
99 * (B.3) Set the other required utilities including setQuantifiersEngine and
100 * setDecisionManager.
101 * (B.4) Call the private initialization method (Theory::finishInit).
103 * Initialization of the second form happens during TheoryEngine::finishInit,
104 * after the quantifiers engine and model objects have been set up.
107 friend class ::CVC4::TheoryEngine
;
110 // Disallow default construction, copy, assignment.
112 Theory(const Theory
&) = delete;
113 Theory
& operator=(const Theory
&) = delete;
115 /** An integer identifying the type of the theory. */
118 /** The SAT search context for the Theory. */
119 context::Context
* d_satContext
;
121 /** The user level assertion context for the Theory. */
122 context::UserContext
* d_userContext
;
124 /** Information about the logic we're operating within. */
125 const LogicInfo
& d_logicInfo
;
127 /** Pointer to proof node manager */
128 ProofNodeManager
* d_pnm
;
131 * The assertFact() queue.
133 * These can not be TNodes as some atoms (such as equalities) are sent
134 * across theories without being stored in a global map.
136 context::CDList
<Assertion
> d_facts
;
138 /** Index into the head of the facts list */
139 context::CDO
<unsigned> d_factsHead
;
141 /** Indices for splitting on the shared terms. */
142 context::CDO
<unsigned> d_sharedTermsIndex
;
144 /** The care graph the theory will use during combination. */
145 CareGraph
* d_careGraph
;
148 * Pointer to the quantifiers engine (or NULL, if quantifiers are not
149 * supported or not enabled). Not owned by the theory.
151 QuantifiersEngine
* d_quantEngine
;
153 /** Pointer to the decision manager. */
154 DecisionManager
* d_decManager
;
157 /** Name of this theory instance. Along with the TheoryId this should provide
158 * an unique string identifier for each instance of a Theory class. We need
159 * this to ensure unique statistics names over multiple theory instances. */
160 std::string d_instanceName
;
162 // === STATISTICS ===
163 /** time spent in check calls */
164 TimerStat d_checkTime
;
165 /** time spent in theory combination */
166 TimerStat d_computeCareGraphTime
;
169 * The only method to add suff to the care graph.
171 void addCarePair(TNode t1
, TNode t2
);
174 * The function should compute the care graph over the shared terms.
175 * The default function returns all the pairs among the shared variables.
177 virtual void computeCareGraph();
180 * A list of shared terms that the theory has.
182 context::CDList
<TNode
> d_sharedTerms
;
184 //---------------------------------- private collect model info
186 * Helper function for computeRelevantTerms
188 void collectTerms(TNode n
,
189 const std::set
<Kind
>& irrKinds
,
190 std::set
<Node
>& termSet
) const;
191 //---------------------------------- end private collect model info
194 * Construct a Theory.
196 * The pair <id, instance> is assumed to uniquely identify this Theory
197 * w.r.t. the SmtEngine.
200 context::Context
* satContext
,
201 context::UserContext
* userContext
,
204 const LogicInfo
& logicInfo
,
205 ProofNodeManager
* pnm
,
206 std::string instance
= ""); // taking : No default.
209 * This is called at shutdown time by the TheoryEngine, just before
210 * destruction. It is important because there are destruction
211 * ordering issues between PropEngine and Theory (based on what
212 * hard-links to Nodes are outstanding). As the fact queue might be
213 * nonempty, we ensure here that it's clear. If you overload this,
214 * you must make an explicit call here to this->Theory::shutdown()
217 virtual void shutdown() { }
220 * The output channel for the Theory.
222 OutputChannel
* d_out
;
225 * The valuation proxy for the Theory to communicate back with the
226 * theory engine (and other theories).
228 Valuation d_valuation
;
230 * Pointer to the official equality engine of this theory, which is owned by
231 * the equality engine manager of TheoryEngine.
233 eq::EqualityEngine
* d_equalityEngine
;
235 * The official equality engine, if we allocated it.
237 std::unique_ptr
<eq::EqualityEngine
> d_allocEqualityEngine
;
239 * The theory state, which contains contexts, valuation, and equality engine.
240 * Notice the theory is responsible for memory management of this class.
242 TheoryState
* d_theoryState
;
244 * The theory inference manager. This is a wrapper around the equality
245 * engine and the output channel. It ensures that the output channel and
246 * the equality engine are used properly.
248 TheoryInferenceManager
* d_inferManager
;
251 * Returns the next assertion in the assertFact() queue.
253 * @return the next assertion in the assertFact() queue
255 inline Assertion
get();
257 const LogicInfo
& getLogicInfo() const {
262 * The theory that owns the uninterpreted sort.
264 static TheoryId s_uninterpretedSortOwner
;
266 void printFacts(std::ostream
& os
) const;
267 void debugPrintFacts() const;
269 /** is legal elimination
271 * Returns true if x -> val is a legal elimination of variable x. This is
272 * useful for ppAssert, when x = val is an entailed equality. This function
273 * determines whether indeed x can be eliminated from the problem via the
274 * substituion x -> val.
276 * The following criteria imply that x -> val is *not* a legal elimination:
277 * (1) If x is contained in val,
278 * (2) If the type of val is not a subtype of the type of x,
279 * (3) If val contains an operator that cannot be evaluated, and produceModels
280 * is true. For example, x -> sqrt(2) is not a legal elimination if we
281 * are producing models. This is because we care about the value of x, and
282 * its value must be computed (approximated) by the non-linear solver.
284 bool isLegalElimination(TNode x
, TNode val
);
285 //--------------------------------- private initialization
287 * Called to set the official equality engine. This should be done by
290 void setEqualityEngine(eq::EqualityEngine
* ee
);
291 /** Called to set the quantifiers engine. */
292 void setQuantifiersEngine(QuantifiersEngine
* qe
);
293 /** Called to set the decision manager. */
294 void setDecisionManager(DecisionManager
* dm
);
296 * Finish theory initialization. At this point, options and the logic
297 * setting are final, the master equality engine and quantifiers
298 * engine (if any) are initialized, and the official equality engine of this
299 * theory has been assigned. This base class implementation
300 * does nothing. This should be called by TheoryEngine only.
302 virtual void finishInit() {}
303 //--------------------------------- end private initialization
306 * This method is called to notify a theory that the node n should
307 * be considered a "shared term" by this theory. This does anything
308 * theory-specific concerning the fact that n is now marked as a shared
309 * term, which is done in addition to explicitly storing n as a shared
310 * term and adding it as a trigger term in the equality engine of this
311 * class (see addSharedTerm).
313 virtual void notifySharedTerm(TNode n
);
316 //--------------------------------- initialization
318 * @return The theory rewriter associated with this theory.
320 virtual TheoryRewriter
* getTheoryRewriter() = 0;
322 * Returns true if this theory needs an equality engine for checking
325 * If this method returns true, then the equality engine manager will
326 * initialize its equality engine field via setEqualityEngine above during
327 * TheoryEngine::finishInit, prior to calling finishInit for this theory.
329 * Additionally, if this method returns true, then this method is required to
330 * update the argument esi with instructions for initializing and setting up
331 * notifications from its equality engine, which is commonly done with
332 * a notifications class (eq::EqualityEngineNotify).
334 virtual bool needsEqualityEngine(EeSetupInfo
& esi
);
336 * Finish theory initialization, standalone version. This is used to
337 * initialize this class if it is not associated with a theory engine.
338 * This allocates the official equality engine of this Theory and then
339 * calls the finishInit method above.
341 void finishInitStandalone();
342 //--------------------------------- end initialization
345 * Return the ID of the theory responsible for the given type.
347 static inline TheoryId
theoryOf(TypeNode typeNode
) {
348 Trace("theory::internal") << "theoryOf(" << typeNode
<< ")" << std::endl
;
350 if (typeNode
.getKind() == kind::TYPE_CONSTANT
) {
351 id
= typeConstantToTheoryId(typeNode
.getConst
<TypeConstant
>());
353 id
= kindToTheoryId(typeNode
.getKind());
355 if (id
== THEORY_BUILTIN
) {
356 Trace("theory::internal") << "theoryOf(" << typeNode
<< ") == " << s_uninterpretedSortOwner
<< std::endl
;
357 return s_uninterpretedSortOwner
;
363 * Returns the ID of the theory responsible for the given node.
365 static TheoryId
theoryOf(options::TheoryOfMode mode
, TNode node
);
368 * Returns the ID of the theory responsible for the given node.
370 static inline TheoryId
theoryOf(TNode node
) {
371 return theoryOf(options::theoryOfMode(), node
);
375 * Set the owner of the uninterpreted sort.
377 static void setUninterpretedSortOwner(TheoryId theory
) {
378 s_uninterpretedSortOwner
= theory
;
382 * Get the owner of the uninterpreted sort.
384 static TheoryId
getUninterpretedSortOwner() {
385 return s_uninterpretedSortOwner
;
389 * Checks if the node is a leaf node of this theory
391 inline bool isLeaf(TNode node
) const {
392 return node
.getNumChildren() == 0 || theoryOf(node
) != d_id
;
396 * Checks if the node is a leaf node of a theory.
398 inline static bool isLeafOf(TNode node
, TheoryId theoryId
) {
399 return node
.getNumChildren() == 0 || theoryOf(node
) != theoryId
;
402 /** Returns true if the assertFact queue is empty*/
403 bool done() const { return d_factsHead
== d_facts
.size(); }
405 * Destructs a Theory.
410 * Subclasses of Theory may add additional efforts. DO NOT CHECK
411 * equality with one of these values (e.g. if STANDARD xxx) but
412 * rather use range checks (or use the helper functions below).
413 * Normally we call QUICK_CHECK or STANDARD; at the leaves we call
419 * Standard effort where theory need not do anything
421 EFFORT_STANDARD
= 50,
423 * Full effort requires the theory make sure its assertions are satisfiable
428 * Last call effort, called after theory combination has completed with
429 * no lemmas and a model is available.
431 EFFORT_LAST_CALL
= 200
434 static inline bool standardEffortOrMore(Effort e
) CVC4_CONST_FUNCTION
435 { return e
>= EFFORT_STANDARD
; }
436 static inline bool standardEffortOnly(Effort e
) CVC4_CONST_FUNCTION
437 { return e
>= EFFORT_STANDARD
&& e
< EFFORT_FULL
; }
438 static inline bool fullEffort(Effort e
) CVC4_CONST_FUNCTION
439 { return e
== EFFORT_FULL
; }
442 * Get the id for this Theory.
444 TheoryId
getId() const {
449 * Get the SAT context associated to this Theory.
451 context::Context
* getSatContext() const {
456 * Get the context associated to this Theory.
458 context::UserContext
* getUserContext() const {
459 return d_userContext
;
463 * Set the output channel associated to this theory.
465 void setOutputChannel(OutputChannel
& out
) {
470 * Get the output channel associated to this theory.
472 OutputChannel
& getOutputChannel() {
477 * Get the valuation associated to this theory.
479 Valuation
& getValuation() {
483 /** Get the equality engine being used by this theory. */
484 eq::EqualityEngine
* getEqualityEngine();
487 * Get the quantifiers engine associated to this theory.
489 QuantifiersEngine
* getQuantifiersEngine() {
490 return d_quantEngine
;
493 /** Get the decision manager associated to this theory. */
494 DecisionManager
* getDecisionManager() { return d_decManager
; }
497 * Expand definitions in the term node. This returns a term that is
498 * equivalent to node. It wraps this term in a TrustNode of kind
499 * TrustNodeKind::REWRITE. If node is unchanged by this method, the
500 * null TrustNode may be returned. This is an optimization to avoid
501 * constructing the trivial equality (= node node) internally within
504 * The purpose of this method is typically to eliminate the operators in node
505 * that are syntax sugar that cannot otherwise be eliminated during rewriting.
506 * For example, division relies on the introduction of an uninterpreted
507 * function for the divide-by-zero case, which we do not introduce with
508 * the rewriter, since this function may be cached in a non-global fashion.
510 * Some theories have kinds that are effectively definitions and should be
511 * expanded before they are handled. Definitions allow a much wider range of
512 * actions than the normal forms given by the rewriter. However no
513 * assumptions can be made about subterms having been expanded or rewritten.
514 * Where possible rewrite rules should be used, definitions should only be
515 * used when rewrites are not possible, for example in handling
516 * under-specified operations using partially defined functions.
518 * Some theories like sets use expandDefinition as a "context
519 * independent preRegisterTerm". This is required for cases where
520 * a theory wants to be notified about a term before preprocessing
521 * and simplification but doesn't necessarily want to rewrite it.
523 virtual TrustNode
expandDefinition(Node node
)
525 // by default, do nothing
526 return TrustNode::null();
530 * Pre-register a term. Done one time for a Node per SAT context level.
532 virtual void preRegisterTerm(TNode
);
535 * Assert a fact in the current context.
537 void assertFact(TNode assertion
, bool isPreregistered
) {
538 Trace("theory") << "Theory<" << getId() << ">::assertFact["
539 << d_satContext
->getLevel() << "](" << assertion
<< ", "
540 << (isPreregistered
? "true" : "false") << ")" << std::endl
;
541 d_facts
.push_back(Assertion(assertion
, isPreregistered
));
544 /** Add shared term to the theory. */
545 void addSharedTerm(TNode node
);
548 * Return the current theory care graph. Theories should overload
549 * computeCareGraph to do the actual computation, and use addCarePair to add
550 * pairs to the care graph.
552 void getCareGraph(CareGraph
* careGraph
);
555 * Return the status of two terms in the current context. Should be
556 * implemented in sub-theories to enable more efficient theory-combination.
558 virtual EqualityStatus
getEqualityStatus(TNode a
, TNode b
);
561 * Return the model value of the give shared term (or null if not available).
563 * TODO (project #39): this method is likely to become deprecated.
565 virtual Node
getModelValue(TNode var
) { return Node::null(); }
567 /** T-propagate new literal assignments in the current context. */
568 virtual void propagate(Effort level
= EFFORT_FULL
) {}
571 * Return an explanation for the literal represented by parameter n
572 * (which was previously propagated by this theory).
574 virtual TrustNode
explain(TNode n
)
576 Unimplemented() << "Theory " << identify()
577 << " propagated a node but doesn't implement the "
578 "Theory::explain() interface!";
579 return TrustNode::null();
582 //--------------------------------- check
584 * Does this theory wish to be called to check at last call effort? This is
585 * the case for any theory that wishes to run when a model is available.
587 virtual bool needsCheckLastEffort() { return false; }
589 * Check the current assignment's consistency.
591 * An implementation of check() is required to either:
592 * - return a conflict on the output channel,
594 * - throw an exception
595 * - or call get() until done() is true.
597 * The standard method for check consists of a loop that processes the entire
598 * fact queue when preCheck returns false. It makes four theory-specific
599 * callbacks, (preCheck, postCheck, preNotifyFact, notifyFact) as described
600 * below. It asserts each fact to the official equality engine when
601 * preNotifyFact returns false.
603 * Theories that use this check method must use an official theory
604 * state object (d_theoryState).
606 * TODO (project #39): this method should be non-virtual, once all theories
607 * conform to the new standard
609 virtual void check(Effort level
= EFFORT_FULL
);
611 * Pre-check, called before the fact queue of the theory is processed.
612 * If this method returns false, then the theory will process its fact
613 * queue. If this method returns true, then the theory has indicated
614 * its check method should finish immediately.
616 virtual bool preCheck(Effort level
= EFFORT_FULL
);
618 * Post-check, called after the fact queue of the theory is processed.
620 virtual void postCheck(Effort level
= EFFORT_FULL
);
622 * Pre-notify fact, return true if the theory processed it. If this
623 * method returns false, then the atom will be added to the equality engine
624 * of the theory and notifyFact will be called with isInternal=false.
626 * Theories that implement check but do not use official equality
627 * engines should always return true for this method.
629 * @param atom The atom
630 * @param polarity Its polarity
631 * @param fact The original literal that was asserted
632 * @param isPrereg Whether the assertion is preregistered
633 * @param isInternal Whether the origin of the fact was internal. If this
634 * is false, the fact was asserted via the fact queue of the theory.
635 * @return true if the theory completely processed this fact, i.e. it does
636 * not need to assert the fact to its equality engine.
638 virtual bool preNotifyFact(
639 TNode atom
, bool pol
, TNode fact
, bool isPrereg
, bool isInternal
);
641 * Notify fact, called immediately after the fact was pushed into the
644 * @param atom The atom
645 * @param polarity Its polarity
646 * @param fact The original literal that was asserted.
647 * @param isInternal Whether the origin of the fact was internal. If this
648 * is false, the fact was asserted via the fact queue of the theory.
650 virtual void notifyFact(TNode atom
, bool pol
, TNode fact
, bool isInternal
);
651 //--------------------------------- end check
653 //--------------------------------- collect model info
655 * Get all relevant information in this theory regarding the current
656 * model. This should be called after a call to check( FULL_EFFORT )
657 * for all theories with no conflicts and no lemmas added.
659 * This method returns true if and only if the equality engine of m is
660 * consistent as a result of this call.
662 * The standard method for collectModelInfo computes the relevant terms,
663 * asserts the theory's equality engine to the model (if necessary) and
664 * then calls computeModelValues.
666 * TODO (project #39): this method should be non-virtual, once all theories
667 * conform to the new standard
669 virtual bool collectModelInfo(TheoryModel
* m
);
671 * Scans the current set of assertions and shared terms top-down
672 * until a theory-leaf is reached, and adds all terms found to
673 * termSet. This is used by collectModelInfo to delimit the set of
674 * terms that should be used when constructing a model.
676 * @param irrKinds The kinds of terms that appear in assertions that should *not*
677 * be included in termSet. Note that the kinds EQUAL and NOT are always
678 * treated as irrelevant kinds.
680 * @param includeShared Whether to include shared terms in termSet. Notice that
681 * shared terms are not influenced by irrKinds.
683 * TODO (project #39): this method will be deleted. The version in
684 * model manager will be used.
686 void computeAssertedTerms(std::set
<Node
>& termSet
,
687 const std::set
<Kind
>& irrKinds
,
688 bool includeShared
= true) const;
690 * Compute terms that are not necessarily part of the assertions or
691 * shared terms that should be considered relevant, add them to termSet.
693 virtual void computeRelevantTerms(std::set
<Node
>& termSet
);
695 * Collect model values, after equality information is added to the model.
696 * The argument termSet is the set of relevant terms returned by
697 * computeRelevantTerms.
699 virtual bool collectModelValues(TheoryModel
* m
,
700 const std::set
<Node
>& termSet
);
701 /** if theories want to do something with model after building, do it here */
702 virtual void postProcessModel( TheoryModel
* m
){ }
703 //--------------------------------- end collect model info
705 //--------------------------------- preprocessing
707 * Statically learn from assertion "in," which has been asserted
708 * true at the top level. The theory should only add (via
709 * ::operator<< or ::append()) to the "learned" builder---it should
710 * *never* clear it. It is a conjunction to add to the formula at
711 * the top-level and may contain other theories' contributions.
713 virtual void ppStaticLearn(TNode in
, NodeBuilder
<>& learned
) { }
715 enum PPAssertStatus
{
716 /** Atom has been solved */
717 PP_ASSERT_STATUS_SOLVED
,
718 /** Atom has not been solved */
719 PP_ASSERT_STATUS_UNSOLVED
,
720 /** Atom is inconsistent */
721 PP_ASSERT_STATUS_CONFLICT
725 * Given a literal, add the solved substitutions to the map, if any.
726 * The method should return true if the literal can be safely removed.
728 virtual PPAssertStatus
ppAssert(TNode in
, SubstitutionMap
& outSubstitutions
);
731 * Given an atom of the theory coming from the input formula, this
732 * method can be overridden in a theory implementation to rewrite
733 * the atom into an equivalent form. This is only called just
734 * before an input atom to the engine. This method returns a TrustNode of
735 * kind TrustNodeKind::REWRITE, which carries information about the proof
736 * generator for the rewrite. Similarly to expandDefinition, this method may
737 * return the null TrustNode if atom is unchanged.
739 virtual TrustNode
ppRewrite(TNode atom
) { return TrustNode::null(); }
742 * Notify preprocessed assertions. Called on new assertions after
743 * preprocessing before they are asserted to theory engine.
745 virtual void ppNotifyAssertions(const std::vector
<Node
>& assertions
) {}
746 //--------------------------------- end preprocessing
749 * A Theory is called with presolve exactly one time per user
750 * check-sat. presolve() is called after preregistration,
751 * rewriting, and Boolean propagation, (other theories'
752 * propagation?), but the notified Theory has not yet had its
753 * check() or propagate() method called. A Theory may empty its
754 * assertFact() queue using get(). A Theory can raise conflicts,
755 * add lemmas, and propagate literals during presolve().
757 * NOTE: The presolve property must be added to the kinds file for
760 virtual void presolve() { }
763 * A Theory is called with postsolve exactly one time per user
764 * check-sat. postsolve() is called after the query has completed
765 * (regardless of whether sat, unsat, or unknown), and after any
766 * model-querying related to the query has been performed.
767 * After this call, the theory will not get another check() or
768 * propagate() call until presolve() is called again. A Theory
769 * cannot raise conflicts, add lemmas, or propagate literals during
772 virtual void postsolve() { }
775 * Notification sent to the theory wheneven the search restarts.
776 * Serves as a good time to do some clean-up work, and you can
777 * assume you're at DL 0 for the purposes of Contexts. This function
778 * should not use the output channel.
780 virtual void notifyRestart() { }
783 * Identify this theory (for debugging, dynamic configuration,
786 virtual std::string
identify() const = 0;
788 /** Set user attribute
789 * This function is called when an attribute is set by a user. In SMT-LIBv2 this is done
790 * via the syntax (! n :attr)
792 virtual void setUserAttribute(const std::string
& attr
, Node n
, std::vector
<Node
> node_values
, std::string str_value
) {
793 Unimplemented() << "Theory " << identify()
794 << " doesn't support Theory::setUserAttribute interface";
797 typedef context::CDList
<Assertion
>::const_iterator assertions_iterator
;
800 * Provides access to the facts queue, primarily intended for theory
801 * debugging purposes.
803 * @return the iterator to the beginning of the fact queue
805 assertions_iterator
facts_begin() const {
806 return d_facts
.begin();
810 * Provides access to the facts queue, primarily intended for theory
811 * debugging purposes.
813 * @return the iterator to the end of the fact queue
815 assertions_iterator
facts_end() const {
816 return d_facts
.end();
819 * Whether facts have been asserted to this theory.
821 * @return true iff facts have been asserted to this theory.
823 bool hasFacts() { return !d_facts
.empty(); }
825 /** Return total number of facts asserted to this theory */
826 size_t numAssertions() {
827 return d_facts
.size();
830 typedef context::CDList
<TNode
>::const_iterator shared_terms_iterator
;
833 * Provides access to the shared terms, primarily intended for theory
834 * debugging purposes.
836 * @return the iterator to the beginning of the shared terms list
838 shared_terms_iterator
shared_terms_begin() const {
839 return d_sharedTerms
.begin();
843 * Provides access to the facts queue, primarily intended for theory
844 * debugging purposes.
846 * @return the iterator to the end of the shared terms list
848 shared_terms_iterator
shared_terms_end() const {
849 return d_sharedTerms
.end();
854 * This is a utility function for constructing a copy of the currently shared terms
855 * in a queriable form. As this is
857 std::unordered_set
<TNode
, TNodeHashFunction
> currentlySharedTerms() const;
860 * This allows the theory to be queried for whether a literal, lit, is
861 * entailed by the theory. This returns a pair of a Boolean and a node E.
863 * If the Boolean is true, then E is a formula that entails lit and E is propositionally
864 * entailed by the assertions to the theory.
866 * If the Boolean is false, it is "unknown" if lit is entailed and E may be
869 * The literal lit is either an atom a or (not a), which must belong to the theory:
870 * There is some TheoryOfMode m s.t. Theory::theoryOf(m, a) == this->getId().
872 * There are NO assumptions that a or the subterms of a have been
873 * preprocessed in any form. This includes ppRewrite, rewriting,
874 * preregistering, registering, definition expansion or ITE removal!
876 * Theories are free to limit the amount of effort they use and so may
877 * always opt to return "unknown". Both "unknown" and "not entailed",
878 * may return for E a non-boolean Node (e.g. Node::null()). (There is no explicit output
879 * for the negation of lit is entailed.)
881 * If lit is theory valid, the return result may be the Boolean constant
884 * If lit is entailed by multiple assertions on the theory's getFact()
885 * queue, a_1, a_2, ... and a_k, this may return E=(and a_1 a_2 ... a_k) or
886 * another theory entailed explanation E=(and (and a_1 a_2) (and a3 a_4) ... a_k)
888 * If lit is entailed by a single assertion on the theory's getFact()
889 * queue, say a, this may return E=a.
891 * The theory may always return false!
893 * Theories may not touch their output stream during an entailment check.
895 * @param lit a literal belonging to the theory.
896 * @return a pair <b,E> s.t. if b is true, then a formula E such that
897 * E |= lit in the theory.
899 virtual std::pair
<bool, Node
> entailmentCheck(TNode lit
);
901 /* get current substitution at an effort
904 * where ( exp[vars[i]] => vars[i] = subs[i] ) holds for all i
906 virtual bool getCurrentSubstitution(int effort
, std::vector
<Node
>& vars
,
907 std::vector
<Node
>& subs
,
908 std::map
<Node
, std::vector
<Node
> >& exp
) {
912 /* is extended function reduced */
913 virtual bool isExtfReduced( int effort
, Node n
, Node on
, std::vector
< Node
>& exp
) { return n
.isConst(); }
916 * Get reduction for node
917 * If return value is not 0, then n is reduced.
918 * If return value <0 then n is reduced SAT-context-independently (e.g. by a
919 * lemma that persists at this user-context level).
920 * If nr is non-null, then ( n = nr ) should be added as a lemma by caller,
921 * and return value should be <0.
923 virtual int getReduction( int effort
, Node n
, Node
& nr
) { return 0; }
926 std::ostream
& operator<<(std::ostream
& os
, theory::Theory::Effort level
);
929 inline theory::Assertion
Theory::get() {
930 Assert(!done()) << "Theory::get() called with assertion queue empty!";
933 Assertion fact
= d_facts
[d_factsHead
];
934 d_factsHead
= d_factsHead
+ 1;
936 Trace("theory") << "Theory::get() => " << fact
<< " (" << d_facts
.size() - d_factsHead
<< " left)" << std::endl
;
938 if(Dump
.isOn("state")) {
939 Dump("state") << AssertCommand(fact
.d_assertion
.toExpr());
945 inline std::ostream
& operator<<(std::ostream
& out
,
946 const CVC4::theory::Theory
& theory
) {
947 return out
<< theory
.identify();
950 inline std::ostream
& operator << (std::ostream
& out
, theory::Theory::PPAssertStatus status
) {
952 case theory::Theory::PP_ASSERT_STATUS_SOLVED
:
953 out
<< "SOLVE_STATUS_SOLVED"; break;
954 case theory::Theory::PP_ASSERT_STATUS_UNSOLVED
:
955 out
<< "SOLVE_STATUS_UNSOLVED"; break;
956 case theory::Theory::PP_ASSERT_STATUS_CONFLICT
:
957 out
<< "SOLVE_STATUS_CONFLICT"; break;
964 }/* CVC4::theory namespace */
965 }/* CVC4 namespace */
967 #endif /* CVC4__THEORY__THEORY_H */