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
;
250 * Whether proofs are enabled
253 bool d_proofsEnabled
;
256 * Returns the next assertion in the assertFact() queue.
258 * @return the next assertion in the assertFact() queue
260 inline Assertion
get();
262 const LogicInfo
& getLogicInfo() const {
267 * The theory that owns the uninterpreted sort.
269 static TheoryId s_uninterpretedSortOwner
;
271 void printFacts(std::ostream
& os
) const;
272 void debugPrintFacts() const;
274 /** is legal elimination
276 * Returns true if x -> val is a legal elimination of variable x. This is
277 * useful for ppAssert, when x = val is an entailed equality. This function
278 * determines whether indeed x can be eliminated from the problem via the
279 * substituion x -> val.
281 * The following criteria imply that x -> val is *not* a legal elimination:
282 * (1) If x is contained in val,
283 * (2) If the type of val is not a subtype of the type of x,
284 * (3) If val contains an operator that cannot be evaluated, and produceModels
285 * is true. For example, x -> sqrt(2) is not a legal elimination if we
286 * are producing models. This is because we care about the value of x, and
287 * its value must be computed (approximated) by the non-linear solver.
289 bool isLegalElimination(TNode x
, TNode val
);
290 //--------------------------------- private initialization
292 * Called to set the official equality engine. This should be done by
295 void setEqualityEngine(eq::EqualityEngine
* ee
);
296 /** Called to set the quantifiers engine. */
297 void setQuantifiersEngine(QuantifiersEngine
* qe
);
298 /** Called to set the decision manager. */
299 void setDecisionManager(DecisionManager
* dm
);
301 * Finish theory initialization. At this point, options and the logic
302 * setting are final, the master equality engine and quantifiers
303 * engine (if any) are initialized, and the official equality engine of this
304 * theory has been assigned. This base class implementation
305 * does nothing. This should be called by TheoryEngine only.
307 virtual void finishInit() {}
308 //--------------------------------- end private initialization
311 * This method is called to notify a theory that the node n should
312 * be considered a "shared term" by this theory. This does anything
313 * theory-specific concerning the fact that n is now marked as a shared
314 * term, which is done in addition to explicitly storing n as a shared
315 * term and adding it as a trigger term in the equality engine of this
316 * class (see addSharedTerm).
318 virtual void notifySharedTerm(TNode n
);
321 //--------------------------------- initialization
323 * @return The theory rewriter associated with this theory.
325 virtual TheoryRewriter
* getTheoryRewriter() = 0;
327 * Returns true if this theory needs an equality engine for checking
330 * If this method returns true, then the equality engine manager will
331 * initialize its equality engine field via setEqualityEngine above during
332 * TheoryEngine::finishInit, prior to calling finishInit for this theory.
334 * Additionally, if this method returns true, then this method is required to
335 * update the argument esi with instructions for initializing and setting up
336 * notifications from its equality engine, which is commonly done with
337 * a notifications class (eq::EqualityEngineNotify).
339 virtual bool needsEqualityEngine(EeSetupInfo
& esi
);
341 * Finish theory initialization, standalone version. This is used to
342 * initialize this class if it is not associated with a theory engine.
343 * This allocates the official equality engine of this Theory and then
344 * calls the finishInit method above.
346 void finishInitStandalone();
347 //--------------------------------- end initialization
350 * Return the ID of the theory responsible for the given type.
352 static inline TheoryId
theoryOf(TypeNode typeNode
) {
353 Trace("theory::internal") << "theoryOf(" << typeNode
<< ")" << std::endl
;
355 if (typeNode
.getKind() == kind::TYPE_CONSTANT
) {
356 id
= typeConstantToTheoryId(typeNode
.getConst
<TypeConstant
>());
358 id
= kindToTheoryId(typeNode
.getKind());
360 if (id
== THEORY_BUILTIN
) {
361 Trace("theory::internal") << "theoryOf(" << typeNode
<< ") == " << s_uninterpretedSortOwner
<< std::endl
;
362 return s_uninterpretedSortOwner
;
368 * Returns the ID of the theory responsible for the given node.
370 static TheoryId
theoryOf(options::TheoryOfMode mode
, TNode node
);
373 * Returns the ID of the theory responsible for the given node.
375 static inline TheoryId
theoryOf(TNode node
) {
376 return theoryOf(options::theoryOfMode(), node
);
380 * Set the owner of the uninterpreted sort.
382 static void setUninterpretedSortOwner(TheoryId theory
) {
383 s_uninterpretedSortOwner
= theory
;
387 * Get the owner of the uninterpreted sort.
389 static TheoryId
getUninterpretedSortOwner() {
390 return s_uninterpretedSortOwner
;
394 * Checks if the node is a leaf node of this theory
396 inline bool isLeaf(TNode node
) const {
397 return node
.getNumChildren() == 0 || theoryOf(node
) != d_id
;
401 * Checks if the node is a leaf node of a theory.
403 inline static bool isLeafOf(TNode node
, TheoryId theoryId
) {
404 return node
.getNumChildren() == 0 || theoryOf(node
) != theoryId
;
407 /** Returns true if the assertFact queue is empty*/
408 bool done() const { return d_factsHead
== d_facts
.size(); }
410 * Destructs a Theory.
415 * Subclasses of Theory may add additional efforts. DO NOT CHECK
416 * equality with one of these values (e.g. if STANDARD xxx) but
417 * rather use range checks (or use the helper functions below).
418 * Normally we call QUICK_CHECK or STANDARD; at the leaves we call
424 * Standard effort where theory need not do anything
426 EFFORT_STANDARD
= 50,
428 * Full effort requires the theory make sure its assertions are satisfiable
433 * Last call effort, called after theory combination has completed with
434 * no lemmas and a model is available.
436 EFFORT_LAST_CALL
= 200
439 static inline bool standardEffortOrMore(Effort e
) CVC4_CONST_FUNCTION
440 { return e
>= EFFORT_STANDARD
; }
441 static inline bool standardEffortOnly(Effort e
) CVC4_CONST_FUNCTION
442 { return e
>= EFFORT_STANDARD
&& e
< EFFORT_FULL
; }
443 static inline bool fullEffort(Effort e
) CVC4_CONST_FUNCTION
444 { return e
== EFFORT_FULL
; }
447 * Get the id for this Theory.
449 TheoryId
getId() const {
454 * Get the SAT context associated to this Theory.
456 context::Context
* getSatContext() const {
461 * Get the context associated to this Theory.
463 context::UserContext
* getUserContext() const {
464 return d_userContext
;
468 * Set the output channel associated to this theory.
470 void setOutputChannel(OutputChannel
& out
) {
475 * Get the output channel associated to this theory.
477 OutputChannel
& getOutputChannel() {
482 * Get the valuation associated to this theory.
484 Valuation
& getValuation() {
488 /** Get the equality engine being used by this theory. */
489 eq::EqualityEngine
* getEqualityEngine();
492 * Get the quantifiers engine associated to this theory.
494 QuantifiersEngine
* getQuantifiersEngine() {
495 return d_quantEngine
;
498 /** Get the decision manager associated to this theory. */
499 DecisionManager
* getDecisionManager() { return d_decManager
; }
502 * Expand definitions in the term node. This returns a term that is
503 * equivalent to node. It wraps this term in a TrustNode of kind
504 * TrustNodeKind::REWRITE. If node is unchanged by this method, the
505 * null TrustNode may be returned. This is an optimization to avoid
506 * constructing the trivial equality (= node node) internally within
509 * The purpose of this method is typically to eliminate the operators in node
510 * that are syntax sugar that cannot otherwise be eliminated during rewriting.
511 * For example, division relies on the introduction of an uninterpreted
512 * function for the divide-by-zero case, which we do not introduce with
513 * the rewriter, since this function may be cached in a non-global fashion.
515 * Some theories have kinds that are effectively definitions and should be
516 * expanded before they are handled. Definitions allow a much wider range of
517 * actions than the normal forms given by the rewriter. However no
518 * assumptions can be made about subterms having been expanded or rewritten.
519 * Where possible rewrite rules should be used, definitions should only be
520 * used when rewrites are not possible, for example in handling
521 * under-specified operations using partially defined functions.
523 * Some theories like sets use expandDefinition as a "context
524 * independent preRegisterTerm". This is required for cases where
525 * a theory wants to be notified about a term before preprocessing
526 * and simplification but doesn't necessarily want to rewrite it.
528 virtual TrustNode
expandDefinition(Node node
)
530 // by default, do nothing
531 return TrustNode::null();
535 * Pre-register a term. Done one time for a Node per SAT context level.
537 virtual void preRegisterTerm(TNode
);
540 * Assert a fact in the current context.
542 void assertFact(TNode assertion
, bool isPreregistered
) {
543 Trace("theory") << "Theory<" << getId() << ">::assertFact["
544 << d_satContext
->getLevel() << "](" << assertion
<< ", "
545 << (isPreregistered
? "true" : "false") << ")" << std::endl
;
546 d_facts
.push_back(Assertion(assertion
, isPreregistered
));
549 /** Add shared term to the theory. */
550 void addSharedTerm(TNode node
);
553 * Return the current theory care graph. Theories should overload
554 * computeCareGraph to do the actual computation, and use addCarePair to add
555 * pairs to the care graph.
557 void getCareGraph(CareGraph
* careGraph
);
560 * Return the status of two terms in the current context. Should be
561 * implemented in sub-theories to enable more efficient theory-combination.
563 virtual EqualityStatus
getEqualityStatus(TNode a
, TNode b
);
566 * Return the model value of the give shared term (or null if not available).
568 * TODO (project #39): this method is likely to become deprecated.
570 virtual Node
getModelValue(TNode var
) { return Node::null(); }
572 /** T-propagate new literal assignments in the current context. */
573 virtual void propagate(Effort level
= EFFORT_FULL
) {}
576 * Return an explanation for the literal represented by parameter n
577 * (which was previously propagated by this theory).
579 virtual TrustNode
explain(TNode n
)
581 Unimplemented() << "Theory " << identify()
582 << " propagated a node but doesn't implement the "
583 "Theory::explain() interface!";
586 //--------------------------------- check
588 * Does this theory wish to be called to check at last call effort? This is
589 * the case for any theory that wishes to run when a model is available.
591 virtual bool needsCheckLastEffort() { return false; }
593 * Check the current assignment's consistency.
595 * An implementation of check() is required to either:
596 * - return a conflict on the output channel,
598 * - throw an exception
599 * - or call get() until done() is true.
601 * The standard method for check consists of a loop that processes the entire
602 * fact queue when preCheck returns false. It makes four theory-specific
603 * callbacks, (preCheck, postCheck, preNotifyFact, notifyFact) as described
604 * below. It asserts each fact to the official equality engine when
605 * preNotifyFact returns false.
607 * Theories that use this check method must use an official theory
608 * state object (d_theoryState).
610 * TODO (project #39): this method should be non-virtual, once all theories
611 * conform to the new standard
613 virtual void check(Effort level
= EFFORT_FULL
);
615 * Pre-check, called before the fact queue of the theory is processed.
616 * If this method returns false, then the theory will process its fact
617 * queue. If this method returns true, then the theory has indicated
618 * its check method should finish immediately.
620 virtual bool preCheck(Effort level
= EFFORT_FULL
);
622 * Post-check, called after the fact queue of the theory is processed.
624 virtual void postCheck(Effort level
= EFFORT_FULL
);
626 * Pre-notify fact, return true if the theory processed it. If this
627 * method returns false, then the atom will be added to the equality engine
628 * of the theory and notifyFact will be called with isInternal=false.
630 * Theories that implement check but do not use official equality
631 * engines should always return true for this method.
633 * @param atom The atom
634 * @param polarity Its polarity
635 * @param fact The original literal that was asserted
636 * @param isPrereg Whether the assertion is preregistered
637 * @param isInternal Whether the origin of the fact was internal. If this
638 * is false, the fact was asserted via the fact queue of the theory.
639 * @return true if the theory completely processed this fact, i.e. it does
640 * not need to assert the fact to its equality engine.
642 virtual bool preNotifyFact(
643 TNode atom
, bool pol
, TNode fact
, bool isPrereg
, bool isInternal
);
645 * Notify fact, called immediately after the fact was pushed into the
648 * @param atom The atom
649 * @param polarity Its polarity
650 * @param fact The original literal that was asserted.
651 * @param isInternal Whether the origin of the fact was internal. If this
652 * is false, the fact was asserted via the fact queue of the theory.
654 virtual void notifyFact(TNode atom
, bool pol
, TNode fact
, bool isInternal
);
655 //--------------------------------- end check
657 //--------------------------------- collect model info
659 * Get all relevant information in this theory regarding the current
660 * model. This should be called after a call to check( FULL_EFFORT )
661 * for all theories with no conflicts and no lemmas added.
663 * This method returns true if and only if the equality engine of m is
664 * consistent as a result of this call.
666 * The standard method for collectModelInfo computes the relevant terms,
667 * asserts the theory's equality engine to the model (if necessary) and
668 * then calls computeModelValues.
670 * TODO (project #39): this method should be non-virtual, once all theories
671 * conform to the new standard
673 virtual bool collectModelInfo(TheoryModel
* m
);
675 * Scans the current set of assertions and shared terms top-down
676 * until a theory-leaf is reached, and adds all terms found to
677 * termSet. This is used by collectModelInfo to delimit the set of
678 * terms that should be used when constructing a model.
680 * @param irrKinds The kinds of terms that appear in assertions that should *not*
681 * be included in termSet. Note that the kinds EQUAL and NOT are always
682 * treated as irrelevant kinds.
684 * @param includeShared Whether to include shared terms in termSet. Notice that
685 * shared terms are not influenced by irrKinds.
687 * TODO (project #39): this method will be deleted. The version in
688 * model manager will be used.
690 void computeAssertedTerms(std::set
<Node
>& termSet
,
691 const std::set
<Kind
>& irrKinds
,
692 bool includeShared
= true) const;
694 * Compute terms that are not necessarily part of the assertions or
695 * shared terms that should be considered relevant, add them to termSet.
697 virtual void computeRelevantTerms(std::set
<Node
>& termSet
);
699 * Collect model values, after equality information is added to the model.
700 * The argument termSet is the set of relevant terms returned by
701 * computeRelevantTerms.
703 virtual bool collectModelValues(TheoryModel
* m
,
704 const std::set
<Node
>& termSet
);
705 /** if theories want to do something with model after building, do it here */
706 virtual void postProcessModel( TheoryModel
* m
){ }
707 //--------------------------------- end collect model info
709 //--------------------------------- preprocessing
711 * Statically learn from assertion "in," which has been asserted
712 * true at the top level. The theory should only add (via
713 * ::operator<< or ::append()) to the "learned" builder---it should
714 * *never* clear it. It is a conjunction to add to the formula at
715 * the top-level and may contain other theories' contributions.
717 virtual void ppStaticLearn(TNode in
, NodeBuilder
<>& learned
) { }
719 enum PPAssertStatus
{
720 /** Atom has been solved */
721 PP_ASSERT_STATUS_SOLVED
,
722 /** Atom has not been solved */
723 PP_ASSERT_STATUS_UNSOLVED
,
724 /** Atom is inconsistent */
725 PP_ASSERT_STATUS_CONFLICT
729 * Given a literal, add the solved substitutions to the map, if any.
730 * The method should return true if the literal can be safely removed.
732 virtual PPAssertStatus
ppAssert(TNode in
, SubstitutionMap
& outSubstitutions
);
735 * Given an atom of the theory coming from the input formula, this
736 * method can be overridden in a theory implementation to rewrite
737 * the atom into an equivalent form. This is only called just
738 * before an input atom to the engine. This method returns a TrustNode of
739 * kind TrustNodeKind::REWRITE, which carries information about the proof
740 * generator for the rewrite. Similarly to expandDefinition, this method may
741 * return the null TrustNode if atom is unchanged.
743 virtual TrustNode
ppRewrite(TNode atom
) { return TrustNode::null(); }
746 * Notify preprocessed assertions. Called on new assertions after
747 * preprocessing before they are asserted to theory engine.
749 virtual void ppNotifyAssertions(const std::vector
<Node
>& assertions
) {}
750 //--------------------------------- end preprocessing
753 * A Theory is called with presolve exactly one time per user
754 * check-sat. presolve() is called after preregistration,
755 * rewriting, and Boolean propagation, (other theories'
756 * propagation?), but the notified Theory has not yet had its
757 * check() or propagate() method called. A Theory may empty its
758 * assertFact() queue using get(). A Theory can raise conflicts,
759 * add lemmas, and propagate literals during presolve().
761 * NOTE: The presolve property must be added to the kinds file for
764 virtual void presolve() { }
767 * A Theory is called with postsolve exactly one time per user
768 * check-sat. postsolve() is called after the query has completed
769 * (regardless of whether sat, unsat, or unknown), and after any
770 * model-querying related to the query has been performed.
771 * After this call, the theory will not get another check() or
772 * propagate() call until presolve() is called again. A Theory
773 * cannot raise conflicts, add lemmas, or propagate literals during
776 virtual void postsolve() { }
779 * Notification sent to the theory wheneven the search restarts.
780 * Serves as a good time to do some clean-up work, and you can
781 * assume you're at DL 0 for the purposes of Contexts. This function
782 * should not use the output channel.
784 virtual void notifyRestart() { }
787 * Identify this theory (for debugging, dynamic configuration,
790 virtual std::string
identify() const = 0;
792 /** Set user attribute
793 * This function is called when an attribute is set by a user. In SMT-LIBv2 this is done
794 * via the syntax (! n :attr)
796 virtual void setUserAttribute(const std::string
& attr
, Node n
, std::vector
<Node
> node_values
, std::string str_value
) {
797 Unimplemented() << "Theory " << identify()
798 << " doesn't support Theory::setUserAttribute interface";
801 typedef context::CDList
<Assertion
>::const_iterator assertions_iterator
;
804 * Provides access to the facts queue, primarily intended for theory
805 * debugging purposes.
807 * @return the iterator to the beginning of the fact queue
809 assertions_iterator
facts_begin() const {
810 return d_facts
.begin();
814 * Provides access to the facts queue, primarily intended for theory
815 * debugging purposes.
817 * @return the iterator to the end of the fact queue
819 assertions_iterator
facts_end() const {
820 return d_facts
.end();
823 * Whether facts have been asserted to this theory.
825 * @return true iff facts have been asserted to this theory.
828 return !d_facts
.empty();
831 /** Return total number of facts asserted to this theory */
832 size_t numAssertions() {
833 return d_facts
.size();
836 typedef context::CDList
<TNode
>::const_iterator shared_terms_iterator
;
839 * Provides access to the shared terms, primarily intended for theory
840 * debugging purposes.
842 * @return the iterator to the beginning of the shared terms list
844 shared_terms_iterator
shared_terms_begin() const {
845 return d_sharedTerms
.begin();
849 * Provides access to the facts queue, primarily intended for theory
850 * debugging purposes.
852 * @return the iterator to the end of the shared terms list
854 shared_terms_iterator
shared_terms_end() const {
855 return d_sharedTerms
.end();
860 * This is a utility function for constructing a copy of the currently shared terms
861 * in a queriable form. As this is
863 std::unordered_set
<TNode
, TNodeHashFunction
> currentlySharedTerms() const;
866 * This allows the theory to be queried for whether a literal, lit, is
867 * entailed by the theory. This returns a pair of a Boolean and a node E.
869 * If the Boolean is true, then E is a formula that entails lit and E is propositionally
870 * entailed by the assertions to the theory.
872 * If the Boolean is false, it is "unknown" if lit is entailed and E may be
875 * The literal lit is either an atom a or (not a), which must belong to the theory:
876 * There is some TheoryOfMode m s.t. Theory::theoryOf(m, a) == this->getId().
878 * There are NO assumptions that a or the subterms of a have been
879 * preprocessed in any form. This includes ppRewrite, rewriting,
880 * preregistering, registering, definition expansion or ITE removal!
882 * Theories are free to limit the amount of effort they use and so may
883 * always opt to return "unknown". Both "unknown" and "not entailed",
884 * may return for E a non-boolean Node (e.g. Node::null()). (There is no explicit output
885 * for the negation of lit is entailed.)
887 * If lit is theory valid, the return result may be the Boolean constant
890 * If lit is entailed by multiple assertions on the theory's getFact()
891 * queue, a_1, a_2, ... and a_k, this may return E=(and a_1 a_2 ... a_k) or
892 * another theory entailed explanation E=(and (and a_1 a_2) (and a3 a_4) ... a_k)
894 * If lit is entailed by a single assertion on the theory's getFact()
895 * queue, say a, this may return E=a.
897 * The theory may always return false!
899 * Theories may not touch their output stream during an entailment check.
901 * @param lit a literal belonging to the theory.
902 * @return a pair <b,E> s.t. if b is true, then a formula E such that
903 * E |= lit in the theory.
905 virtual std::pair
<bool, Node
> entailmentCheck(TNode lit
);
907 /* get current substitution at an effort
910 * where ( exp[vars[i]] => vars[i] = subs[i] ) holds for all i
912 virtual bool getCurrentSubstitution(int effort
, std::vector
<Node
>& vars
,
913 std::vector
<Node
>& subs
,
914 std::map
<Node
, std::vector
<Node
> >& exp
) {
918 /* is extended function reduced */
919 virtual bool isExtfReduced( int effort
, Node n
, Node on
, std::vector
< Node
>& exp
) { return n
.isConst(); }
922 * Get reduction for node
923 * If return value is not 0, then n is reduced.
924 * If return value <0 then n is reduced SAT-context-independently (e.g. by a
925 * lemma that persists at this user-context level).
926 * If nr is non-null, then ( n = nr ) should be added as a lemma by caller,
927 * and return value should be <0.
929 virtual int getReduction( int effort
, Node n
, Node
& nr
) { return 0; }
931 /** Turn on proof-production mode. */
932 void produceProofs() { d_proofsEnabled
= true; }
935 std::ostream
& operator<<(std::ostream
& os
, theory::Theory::Effort level
);
938 inline theory::Assertion
Theory::get() {
939 Assert(!done()) << "Theory::get() called with assertion queue empty!";
942 Assertion fact
= d_facts
[d_factsHead
];
943 d_factsHead
= d_factsHead
+ 1;
945 Trace("theory") << "Theory::get() => " << fact
<< " (" << d_facts
.size() - d_factsHead
<< " left)" << std::endl
;
947 if(Dump
.isOn("state")) {
948 Dump("state") << AssertCommand(fact
.d_assertion
.toExpr());
954 inline std::ostream
& operator<<(std::ostream
& out
,
955 const CVC4::theory::Theory
& theory
) {
956 return out
<< theory
.identify();
959 inline std::ostream
& operator << (std::ostream
& out
, theory::Theory::PPAssertStatus status
) {
961 case theory::Theory::PP_ASSERT_STATUS_SOLVED
:
962 out
<< "SOLVE_STATUS_SOLVED"; break;
963 case theory::Theory::PP_ASSERT_STATUS_UNSOLVED
:
964 out
<< "SOLVE_STATUS_UNSOLVED"; break;
965 case theory::Theory::PP_ASSERT_STATUS_CONFLICT
:
966 out
<< "SOLVE_STATUS_CONFLICT"; break;
973 }/* CVC4::theory namespace */
974 }/* CVC4 namespace */
976 #endif /* CVC4__THEORY__THEORY_H */