74 lines
2.6 KiB
C++
74 lines
2.6 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 "util/buffer.h"
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#include "kernel/expr.h"
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#include "kernel/expr_maps.h"
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namespace lean {
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/** \brief Implements deep copy of kernel expressions. */
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class deep_copy_fn {
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expr_cell_map<expr> m_cache;
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expr save_result(expr const & a, expr && r, bool shared) {
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if (shared)
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m_cache.insert(std::make_pair(a.raw(), r));
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return r;
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}
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optional<expr> apply(optional<expr> const & a) {
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if (a)
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return some_expr(apply(*a));
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else
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return a;
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}
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expr apply(expr const & a) {
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bool sh = false;
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if (is_shared(a)) {
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auto r = m_cache.find(a.raw());
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if (r != m_cache.end())
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return r->second;
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sh = true;
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}
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switch (a.kind()) {
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case expr_kind::Var: case expr_kind::Constant: case expr_kind::Type: case expr_kind::Value:
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return save_result(a, copy(a), sh);
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case expr_kind::App: {
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buffer<expr> new_args;
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for (expr const & old_arg : args(a))
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new_args.push_back(apply(old_arg));
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return save_result(a, mk_app(new_args), sh);
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}
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case expr_kind::Eq: return save_result(a, mk_eq(apply(eq_lhs(a)), apply(eq_rhs(a))), sh);
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case expr_kind::Lambda: return save_result(a, mk_lambda(abst_name(a), apply(abst_domain(a)), apply(abst_body(a))), sh);
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case expr_kind::Pi: return save_result(a, mk_pi(abst_name(a), apply(abst_domain(a)), apply(abst_body(a))), sh);
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case expr_kind::Let: return save_result(a, mk_let(let_name(a), apply(let_type(a)), apply(let_value(a)), apply(let_body(a))), sh);
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case expr_kind::MetaVar:
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return save_result(a,
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update_metavar(a, [&](local_entry const & e) -> local_entry {
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if (e.is_inst())
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return mk_inst(e.s(), apply(e.v()));
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else
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return e;
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}),
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sh);
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}
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lean_unreachable(); // LCOV_EXCL_LINE
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}
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public:
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/**
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\brief Return a new expression that is equal to the given
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argument, but does not share any memory cell with it.
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*/
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expr operator()(expr const & a) { return apply(a); }
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};
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expr deep_copy(expr const & e) {
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return deep_copy_fn()(e);
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}
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}
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