44 lines
1 KiB
C++
44 lines
1 KiB
C++
/*
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Copyright (c) 2013 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/expr_pair.h"
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#include "kernel/kernel.h"
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namespace lean {
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bool is_equality(expr const & e) {
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return is_eq(e) || is_iff(e) || is_heq(e);
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}
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bool is_equality(expr const & e, expr & lhs, expr & rhs) {
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if (is_eq(e)) {
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lhs = arg(e, 2);
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rhs = arg(e, 3);
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return true;
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} else if (is_iff(e)) {
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lhs = arg(e, 1);
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rhs = arg(e, 2);
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return true;
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} else if (is_heq(e)) {
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lhs = heq_lhs(e);
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rhs = heq_rhs(e);
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return true;
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} else {
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return false;
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}
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}
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expr_pair get_equality_args(expr const & e) {
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if (is_eq(e)) {
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return mk_pair(arg(e, 2), arg(e, 3));
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} else if (is_iff(e)) {
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return mk_pair(arg(e, 1), arg(e, 2));
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} else if (is_heq(e)) {
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return mk_pair(heq_lhs(e), heq_rhs(e));
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} else {
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lean_unreachable(); // LCOV_EXCL_LINE
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}
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}
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}
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