3e1fd06903
After this commit, a value of type 'expr' cannot be a reference to nullptr. This commit also fixes several bugs due to the use of 'null' expressions. TODO: do the same for kernel objects, sexprs, etc. Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
115 lines
3.8 KiB
C++
115 lines
3.8 KiB
C++
/*
|
|
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
|
|
Released under Apache 2.0 license as described in the file LICENSE.
|
|
|
|
Author: Leonardo de Moura
|
|
*/
|
|
#pragma once
|
|
#include <memory>
|
|
#include <utility>
|
|
#include "util/buffer.h"
|
|
#include "kernel/expr.h"
|
|
#include "kernel/expr_sets.h"
|
|
|
|
namespace lean {
|
|
/**
|
|
\brief Template for implementing expression visitors.
|
|
The argument \c F must be a function object containing the method
|
|
<code>
|
|
void operator()(expr const & e, unsigned offset)
|
|
</code>
|
|
The \c offset is the number of binders under which \c e occurs.
|
|
*/
|
|
template<typename F, bool CacheAtomic = false>
|
|
class for_each_fn {
|
|
std::unique_ptr<expr_cell_offset_set> m_visited;
|
|
F m_f;
|
|
static_assert(std::is_same<typename std::result_of<F(expr const &, unsigned)>::type, bool>::value,
|
|
"for_each_fn: return type of m_f is not bool");
|
|
|
|
void apply(expr const & e, unsigned offset) {
|
|
buffer<std::pair<expr const &, unsigned>> todo;
|
|
todo.emplace_back(e, offset);
|
|
while (true) {
|
|
begin_loop:
|
|
if (todo.empty())
|
|
break;
|
|
auto p = todo.back();
|
|
todo.pop_back();
|
|
expr const & e = p.first;
|
|
unsigned offset = p.second;
|
|
if (!CacheAtomic) {
|
|
switch (e.kind()) {
|
|
case expr_kind::Constant:
|
|
if (!const_type(e)) {
|
|
// only constants without cached types are considered atomic
|
|
m_f(e, offset);
|
|
goto begin_loop;
|
|
}
|
|
break;
|
|
case expr_kind::Type: case expr_kind::Value:
|
|
case expr_kind::Var: case expr_kind::MetaVar:
|
|
m_f(e, offset);
|
|
goto begin_loop;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (is_shared(e)) {
|
|
expr_cell_offset p(e.raw(), offset);
|
|
if (!m_visited)
|
|
m_visited.reset(new expr_cell_offset_set());
|
|
if (m_visited->find(p) != m_visited->end())
|
|
goto begin_loop;
|
|
m_visited->insert(p);
|
|
}
|
|
|
|
if (!m_f(e, offset))
|
|
goto begin_loop;
|
|
|
|
switch (e.kind()) {
|
|
case expr_kind::Constant:
|
|
if (const_type(e))
|
|
todo.emplace_back(*const_type(e), offset);
|
|
goto begin_loop;
|
|
case expr_kind::Type: case expr_kind::Value:
|
|
case expr_kind::Var: case expr_kind::MetaVar:
|
|
goto begin_loop;
|
|
case expr_kind::App: {
|
|
auto it = end_args(e);
|
|
auto begin = begin_args(e);
|
|
while (it != begin) {
|
|
--it;
|
|
todo.emplace_back(*it, offset);
|
|
}
|
|
goto begin_loop;
|
|
}
|
|
case expr_kind::Eq:
|
|
todo.emplace_back(eq_rhs(e), offset);
|
|
todo.emplace_back(eq_lhs(e), offset);
|
|
goto begin_loop;
|
|
case expr_kind::Lambda:
|
|
case expr_kind::Pi:
|
|
todo.emplace_back(abst_body(e), offset + 1);
|
|
todo.emplace_back(abst_domain(e), offset);
|
|
goto begin_loop;
|
|
case expr_kind::Let:
|
|
todo.emplace_back(let_body(e), offset + 1);
|
|
todo.emplace_back(let_value(e), offset);
|
|
if (let_type(e))
|
|
todo.emplace_back(*let_type(e), offset);
|
|
goto begin_loop;
|
|
}
|
|
}
|
|
}
|
|
public:
|
|
for_each_fn(F const & f):m_f(f) {}
|
|
void operator()(expr const & e) { apply(e, 0); }
|
|
};
|
|
|
|
template<typename F>
|
|
void for_each(expr const & e, F f) {
|
|
return for_each_fn<F>(f)(e);
|
|
}
|
|
}
|