lean2/src/library/deep_copy.cpp

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/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/buffer.h"
#include "kernel/expr.h"
#include "kernel/expr_maps.h"
namespace lean {
expr copy(expr const & a) {
switch (a.kind()) {
case expr_kind::Var: return mk_var(var_idx(a));
case expr_kind::Constant: return mk_constant(const_name(a), const_levels(a));
case expr_kind::Sort: return mk_sort(sort_level(a));
case expr_kind::Macro: return mk_macro(to_macro(a)->m_definition, macro_num_args(a), macro_args(a));
case expr_kind::App: return mk_app(app_fn(a), app_arg(a));
case expr_kind::Lambda: return mk_lambda(binding_name(a), binding_domain(a), binding_body(a), binding_info(a));
case expr_kind::Pi: return mk_pi(binding_name(a), binding_domain(a), binding_body(a), binding_info(a));
case expr_kind::Let: return mk_let(let_name(a), let_type(a), let_value(a), let_body(a));
case expr_kind::Meta: return mk_metavar(mlocal_name(a), mlocal_type(a));
case expr_kind::Local: return mk_local(mlocal_name(a), local_pp_name(a), mlocal_type(a));
}
lean_unreachable(); // LCOV_EXCL_LINE
}
/** \brief Implements deep copy of kernel expressions. */
class deep_copy_fn {
expr_cell_map<expr> m_cache;
expr apply(expr const & a) {
bool sh = false;
if (is_shared(a)) {
auto r = m_cache.find(a.raw());
if (r != m_cache.end())
return r->second;
sh = true;
}
expr r;
switch (a.kind()) {
case expr_kind::Var:
case expr_kind::Constant:
case expr_kind::Sort:
case expr_kind::Macro: r = copy(a); break;
case expr_kind::App: r = mk_app(apply(app_fn(a)), apply(app_arg(a))); break;
case expr_kind::Lambda: r = mk_lambda(binding_name(a), apply(binding_domain(a)), apply(binding_body(a))); break;
case expr_kind::Pi: r = mk_pi(binding_name(a), apply(binding_domain(a)), apply(binding_body(a))); break;
case expr_kind::Let: r = mk_let(let_name(a), apply(let_type(a)), apply(let_value(a)), apply(let_body(a))); break;
case expr_kind::Meta: r = mk_metavar(mlocal_name(a), apply(mlocal_type(a))); break;
case expr_kind::Local: r = mk_local(mlocal_name(a), local_pp_name(a), apply(mlocal_type(a))); break;
}
if (sh)
m_cache.insert(std::make_pair(a.raw(), r));
return r;
}
public:
/**
\brief Return a new expression that is equal to the given
argument, but does not share any memory cell with it.
*/
expr operator()(expr const & a) { return apply(a); }
};
expr deep_copy(expr const & e) { return deep_copy_fn()(e); }
}