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https://github.com/Z3Prover/z3
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225 lines
9.6 KiB
C++
225 lines
9.6 KiB
C++
/*++
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Copyright (c) 2011 Microsoft Corporation
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Module Name:
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theory_seq.h
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Abstract:
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Native theory solver for sequences.
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Author:
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Nikolaj Bjorner (nbjorner) 2015-6-12
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Revision History:
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--*/
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#ifndef THEORY_SEQ_H_
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#define THEORY_SEQ_H_
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#include "smt_theory.h"
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#include "seq_decl_plugin.h"
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#include "theory_seq_empty.h"
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#include "th_rewriter.h"
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#include "union_find.h"
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#include "ast_trail.h"
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namespace smt {
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class theory_seq : public theory {
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struct config {
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static const bool preserve_roots = true;
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static const unsigned max_trail_sz = 16;
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static const unsigned factor = 2;
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typedef small_object_allocator allocator;
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};
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typedef scoped_dependency_manager<enode_pair> enode_pair_dependency_manager;
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typedef enode_pair_dependency_manager::dependency enode_pair_dependency;
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struct enode_pair_dependency_array_config : public config {
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typedef enode_pair_dependency* value;
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typedef dummy_value_manager<value> value_manager;
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static const bool ref_count = false;
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};
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typedef parray_manager<enode_pair_dependency_array_config> enode_pair_dependency_array_manager;
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typedef enode_pair_dependency_array_manager::ref enode_pair_dependency_array;
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typedef union_find<theory_seq> th_union_find;
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typedef trail_stack<theory_seq> th_trail_stack;
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class solution_map {
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enum map_update { INS, DEL };
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typedef obj_map<expr, std::pair<expr*, enode_pair_dependency*> > map_t;
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ast_manager& m;
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enode_pair_dependency_manager& m_dm;
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map_t m_map;
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expr_ref_vector m_lhs, m_rhs;
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ptr_vector<enode_pair_dependency> m_deps;
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svector<map_update> m_updates;
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unsigned_vector m_limit;
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void add_trail(map_update op, expr* l, expr* r, enode_pair_dependency* d);
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public:
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solution_map(ast_manager& m, enode_pair_dependency_manager& dm): m(m), m_dm(dm), m_lhs(m), m_rhs(m) {}
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bool empty() const { return m_map.empty(); }
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void update(expr* e, expr* r, enode_pair_dependency* d);
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expr* find(expr* e, enode_pair_dependency*& d);
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void push_scope() { m_limit.push_back(m_updates.size()); }
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void pop_scope(unsigned num_scopes);
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void display(std::ostream& out) const;
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};
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class exclusion_table {
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typedef obj_pair_hashtable<expr, expr> table_t;
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ast_manager& m;
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table_t m_table;
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expr_ref_vector m_lhs, m_rhs;
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unsigned_vector m_limit;
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public:
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exclusion_table(ast_manager& m): m(m), m_lhs(m), m_rhs(m) {}
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~exclusion_table() { }
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bool empty() const { return m_table.empty(); }
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void update(expr* e, expr* r);
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bool contains(expr* e, expr* r) const;
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void push_scope() { m_limit.push_back(m_lhs.size()); }
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void pop_scope(unsigned num_scopes);
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void display(std::ostream& out) const;
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};
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class eval_cache {
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obj_map<expr, expr*> m_map;
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expr_ref_vector m_trail;
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public:
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eval_cache(ast_manager& m): m_trail(m) {}
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bool find(expr* v, expr*& r) const { return m_map.find(v, r); }
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void insert(expr* v, expr* r) { m_trail.push_back(v); m_trail.push_back(r); m_map.insert(v, r); }
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void reset() { m_map.reset(); m_trail.reset(); }
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};
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struct stats {
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stats() { reset(); }
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void reset() { memset(this, 0, sizeof(stats)); }
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unsigned m_num_splits;
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unsigned m_num_reductions;
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};
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ast_manager& m;
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small_object_allocator m_alloc;
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enode_pair_dependency_array_config::value_manager m_dep_array_value_manager;
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enode_pair_dependency_manager m_dm;
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enode_pair_dependency_array_manager m_dam;
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solution_map m_rep; // unification representative.
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vector<expr_array> m_lhs, m_rhs; // persistent sets of equalities.
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vector<enode_pair_dependency_array> m_deps; // persistent sets of dependencies.
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eval_cache m_cache;
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ast2ast_trailmap<sort, func_decl> m_sort2len_fn; // length functions per sort.
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seq_factory* m_factory; // value factory
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expr_ref_vector m_ineqs; // inequalities to check solution against
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exclusion_table m_exclude; // set of asserted disequalities.
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expr_ref_vector m_axioms; // list of axioms to add.
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unsigned m_axioms_head; // index of first axiom to add.
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unsigned m_branch_variable_head; // index of first equation to examine.
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bool m_incomplete; // is the solver (clearly) incomplete for the fragment.
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bool m_has_length; // is length applied
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bool m_model_completion; // during model construction, invent values in canonizer
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th_rewriter m_rewrite;
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seq_util m_util;
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arith_util m_autil;
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th_trail_stack m_trail_stack;
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stats m_stats;
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symbol m_prefix_sym;
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symbol m_suffix_sym;
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symbol m_contains_left_sym;
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symbol m_contains_right_sym;
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symbol m_left_sym; // split variable left part
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symbol m_right_sym; // split variable right part
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virtual final_check_status final_check_eh();
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virtual bool internalize_atom(app*, bool);
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virtual bool internalize_term(app*);
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virtual void internalize_eq_eh(app * atom, bool_var v);
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virtual void new_eq_eh(theory_var, theory_var);
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virtual void new_diseq_eh(theory_var, theory_var);
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virtual void assign_eq(bool_var v, bool is_true);
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virtual bool can_propagate();
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virtual void propagate();
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virtual void push_scope_eh();
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virtual void pop_scope_eh(unsigned num_scopes);
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virtual void restart_eh();
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virtual void relevant_eh(app* n);
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virtual theory* mk_fresh(context* new_ctx) { return alloc(theory_seq, new_ctx->get_manager()); }
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virtual char const * get_name() const { return "seq"; }
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virtual theory_var mk_var(enode* n);
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virtual void apply_sort_cnstr(enode* n, sort* s);
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virtual void display(std::ostream & out) const;
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virtual void collect_statistics(::statistics & st) const;
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virtual model_value_proc * mk_value(enode * n, model_generator & mg);
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virtual void init_model(model_generator & mg);
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// final check
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bool check_ineqs(); // check if inequalities are violated.
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bool simplify_and_solve_eqs(); // solve unitary equalities
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bool branch_variable(); // branch on a variable
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bool split_variable(); // split a variable
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bool pre_process_eqs(bool simplify_or_solve);
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bool simplify_eqs();
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bool simplify_eq(expr* l, expr* r, enode_pair_dependency* dep);
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bool solve_unit_eq(expr* l, expr* r, enode_pair_dependency* dep);
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bool solve_basic_eqs();
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// asserting consequences
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void propagate_lit(enode_pair_dependency* dep, literal lit);
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void propagate_eq(enode_pair_dependency* dep, enode* n1, enode* n2);
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void propagate_eq(bool_var v, expr* e1, expr* e2);
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void set_conflict(enode_pair_dependency* dep);
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bool find_branch_candidate(expr* l, ptr_vector<expr> const& rs);
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bool assume_equality(expr* l, expr* r);
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// variable solving utilities
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bool occurs(expr* a, expr* b);
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bool is_var(expr* b);
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void add_solution(expr* l, expr* r, enode_pair_dependency* dep);
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bool is_left_select(expr* a, expr*& b);
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bool is_right_select(expr* a, expr*& b);
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expr_ref canonize(expr* e, enode_pair_dependency*& eqs);
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expr_ref expand(expr* e, enode_pair_dependency*& eqs);
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void add_dependency(enode_pair_dependency*& dep, enode* a, enode* b);
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// terms whose meaning are encoded using axioms.
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void enque_axiom(expr* e);
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void deque_axiom(expr* e);
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void add_axiom(literal l1, literal l2 = null_literal, literal l3 = null_literal, literal l4 = null_literal);
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void add_indexof_axiom(expr* e);
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void add_replace_axiom(expr* e);
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void add_extract_axiom(expr* e);
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void add_length_axiom(expr* n);
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void add_length_unit_axiom(expr* n);
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void add_length_empty_axiom(expr* n);
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void add_length_concat_axiom(expr* n);
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void add_length_string_axiom(expr* n);
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void add_at_axiom(expr* n);
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literal mk_literal(expr* n);
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void tightest_prefix(expr* s, expr* x, literal lit, literal lit2 = null_literal);
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expr* mk_sub(expr* a, expr* b);
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expr_ref mk_skolem(symbol const& s, expr* e1, expr* e2 = 0, expr* e3 = 0);
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void set_incomplete(app* term);
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// diagnostics
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void display_equations(std::ostream& out) const;
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void display_deps(std::ostream& out, enode_pair_dependency* deps) const;
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public:
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theory_seq(ast_manager& m);
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virtual ~theory_seq();
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};
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};
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#endif /* THEORY_SEQ_H_ */
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