z3-z3-4.13.0.src.ast.substitution.unifier.h Maven / Gradle / Ivy
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/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
unifier.h
Abstract:
Quasi-linear unification.
Author:
Leonardo de Moura (leonardo) 2008-01-28.
Revision History:
--*/
#pragma once
#include "ast/ast.h"
#include "ast/substitution/substitution.h"
/**
\brief Functor for unifying expressions.
It implements a quasi-linear unification algorithm.
It has support for two different variable banks: left and right.
That is, variable i in left bank is considered different from
variable i in the right bank. This feature allows us to avoid
unnecessary variable renaming.
*/
class unifier {
typedef std::pair entry;
ast_manager & m_manager;
substitution * m_subst;
svector m_todo;
expr_offset_map m_find;
expr_offset_map m_size;
bool m_last_call_succeeded;
expr_offset find(expr_offset n);
void save_var(expr_offset const & p, expr_offset const & t);
void union1(expr_offset const & n1, expr_offset const & n2);
void union2(expr_offset n1, expr_offset n2);
void reset(unsigned num_offsets);
bool unify_core(expr_offset p1, expr_offset p2);
public:
unifier(ast_manager & m):m_manager(m), m_last_call_succeeded(false) {}
/**
\brief Unify the given expressions. Return true if succeeded,
and store the result in the given substitution.
If use_offsets is true, then the variables in the given expressions are assumed to be
in different banks.
*/
bool operator()(unsigned num_exprs, expr ** es, substitution & s, bool use_offsets = true);
bool operator()(expr * e1, expr * e2, substitution & s, bool use_offsets = true);
};