65 lines
1.8 KiB
C++
65 lines
1.8 KiB
C++
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/*
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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 <algorithm>
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#include "free_vars.h"
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#include "sets.h"
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namespace lean {
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class has_free_var_functor {
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expr_cell_offset_set m_visited;
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public:
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bool apply(expr const & e, unsigned offset) {
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// handle easy cases
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switch (e.kind()) {
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case expr_kind::Constant: case expr_kind::Prop: case expr_kind::Type: case expr_kind::Numeral:
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return false;
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case expr_kind::Var:
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return get_var_idx(e) >= offset;
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case expr_kind::App: case expr_kind::Lambda: case expr_kind::Pi:
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break;
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}
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if (e.raw()->is_closed())
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return false;
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if (is_shared(e)) {
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expr_cell_offset p(e.raw(), offset);
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if (m_visited.find(p) != m_visited.end())
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return false;
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m_visited.insert(p);
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}
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bool result = false;
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switch (e.kind()) {
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case expr_kind::Constant: case expr_kind::Prop: case expr_kind::Type: case expr_kind::Numeral: case expr_kind::Var:
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// easy cases were already handled
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lean_unreachable(); return false;
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case expr_kind::App:
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result = std::any_of(begin_args(e), end_args(e), [=](expr const & arg){ return apply(arg, offset); });
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break;
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case expr_kind::Lambda:
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case expr_kind::Pi:
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result = apply(get_abs_type(e), offset) || apply(get_abs_expr(e), offset + 1);
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break;
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}
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if (!result)
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e.raw()->set_closed();
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return result;
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}
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};
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bool has_free_vars(expr const & e) {
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has_free_var_functor f;
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return f.apply(e, 0);
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}
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}
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