lean2/src/library/head_map.h

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/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#pragma once
#include "util/rb_map.h"
#include "util/list.h"
#include "kernel/expr.h"
namespace lean {
struct head_index {
expr_kind m_kind;
name m_const_name;
explicit head_index(expr_kind k = expr_kind::Var):m_kind(k) {}
explicit head_index(name const & c):m_kind(expr_kind::Constant), m_const_name(c) {}
head_index(expr const & e);
struct cmp {
int operator()(head_index const & i1, head_index const & i2) const;
};
};
/**
\brief Very simple indexing data-structure that allow us to map the head symbol of an expression to
a list of values.
The index is the expression kind and a name (if it is a constant).
This index is very naive, but it is effective for many applications.
*/
template<typename V>
class head_map {
rb_map<head_index, list<V>, head_index::cmp> m_map;
public:
bool empty() const { return m_map.empty(); }
bool contains(head_index const & h) const { return m_map.contains(h); }
list<V> const * find(head_index const & h) const { return m_map.find(h); }
void erase(head_index const & h) { m_map.erase(h); }
void erase_entry(head_index const & h, V const & v) {
if (auto it = m_map.find(h)) {
auto new_vs = filter(*it, [&](V const & v2) { return v != v2; });
if (!new_vs)
m_map.erase(h);
else
m_map.insert(h, new_vs);
}
}
void insert(head_index const & h, V const & v) {
if (auto it = m_map.find(h))
m_map.insert(h, cons(v, filter(*it, [&](V const & v2) { return v != v2; })));
else
m_map.insert(h, list<V>(v));
}
template<typename F> void for_each(F && f) const { m_map.for_each(f); }
template<typename F> void for_each_entry(F && f) const {
m_map.for_each([&](head_index const & h, list<V> const & vs) {
for (V const & v : vs)
f(h, v);
});
}
};
}