62 lines
2.1 KiB
C++
62 lines
2.1 KiB
C++
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/*
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Copyright (c) 2015 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include "library/blast/assert_cc_action.h"
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#include "library/blast/congruence_closure.h"
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#include "library/blast/blast.h"
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#include "library/blast/trace.h"
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namespace lean {
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namespace blast {
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static unsigned g_ext_id = 0;
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struct cc_branch_extension : public branch_extension {
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congruence_closure m_cc;
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cc_branch_extension() {}
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cc_branch_extension(cc_branch_extension const & o):m_cc(o.m_cc) {}
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virtual ~cc_branch_extension() {}
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virtual branch_extension * clone() { return new cc_branch_extension(*this); }
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};
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void initialize_assert_cc_action() {
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g_ext_id = register_branch_extension(new cc_branch_extension());
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}
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void finalize_assert_cc_action() {}
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static congruence_closure & get_cc() {
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return static_cast<cc_branch_extension&>(curr_state().get_extension(g_ext_id)).m_cc;
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}
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action_result assert_cc_action(hypothesis_idx hidx) {
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congruence_closure & cc = get_cc();
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cc.add(hidx);
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if (cc.is_inconsistent()) {
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try {
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app_builder & b = get_app_builder();
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expr false_proof = *cc.get_inconsistency_proof();
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trace_action("contradiction by congruence closure");
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return action_result(b.mk_false_rec(curr_state().get_target(), false_proof));
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} catch (app_builder_exception &) {
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return action_result::failed();
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}
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} else {
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expr const & target = curr_state().get_target();
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name R; expr lhs, rhs;
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if (is_relation_app(target, R, lhs, rhs) && cc.is_eqv(R, lhs, rhs)) {
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expr proof = *cc.get_eqv_proof(R, lhs, rhs);
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trace_action("equivalence by congruence closure");
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return action_result(proof);
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} else if (is_prop(target) && !is_false(target) && cc.proved(target)) {
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expr proof = *cc.get_proof(target);
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trace_action("equivalent to true by congruence closure");
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return action_result(proof);
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} else {
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return action_result::new_branch();
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}
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}
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}
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}}
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