54 lines
1.6 KiB
C++
54 lines
1.6 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 "expr.h"
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#include "maps.h"
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#include "buffer.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 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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expr r;
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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::Numeral:
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r = copy(a); break; // shallow copy is equivalent to deep copy for these ones.
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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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r = app(new_args.size(), new_args.data());
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break;
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}
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case expr_kind::Lambda: r = lambda(abst_name(a), apply(abst_type(a)), apply(abst_body(a))); break;
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case expr_kind::Pi: r = pi(abst_name(a), apply(abst_type(a)), apply(abst_body(a))); break;
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}
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if (sh)
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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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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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