603dafbaf7
We simulate it in the following way:
1- An opaque 'let'-expressions (let x : t := v in b) is encoded as
((fun (x : t), b) v)
We also use a macro (let-macro) to mark this pattern.
Thus, the pretty-printer knows how to display it correctly.
2- Transparent 'let'-expressions are eagerly expanded by the parser.
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
70 lines
2 KiB
C++
70 lines
2 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 <utility>
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#include "kernel/for_each_fn.h"
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namespace lean {
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void for_each_fn::apply(expr const & e, unsigned offset) {
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buffer<std::pair<expr const &, unsigned>> todo;
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todo.emplace_back(e, offset);
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while (true) {
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begin_loop:
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if (todo.empty())
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break;
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auto p = todo.back();
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todo.pop_back();
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expr const & e = p.first;
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unsigned offset = p.second;
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switch (e.kind()) {
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case expr_kind::Constant: case expr_kind::Var:
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case expr_kind::Sort:
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m_f(e, offset);
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goto begin_loop;
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default:
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break;
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}
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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)
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m_visited.reset(new expr_cell_offset_set());
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if (m_visited->find(p) != m_visited->end())
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goto begin_loop;
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m_visited->insert(p);
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}
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if (!m_f(e, offset))
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goto begin_loop;
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switch (e.kind()) {
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case expr_kind::Constant: case expr_kind::Var:
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case expr_kind::Sort:
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goto begin_loop;
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case expr_kind::Meta: case expr_kind::Local:
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todo.emplace_back(mlocal_type(e), offset);
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goto begin_loop;
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case expr_kind::Macro: {
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unsigned i = macro_num_args(e);
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while (i > 0) {
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--i;
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todo.emplace_back(macro_arg(e, i), offset);
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}
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goto begin_loop;
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}
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case expr_kind::App:
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todo.emplace_back(app_arg(e), offset);
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todo.emplace_back(app_fn(e), offset);
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goto begin_loop;
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case expr_kind::Lambda: case expr_kind::Pi:
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todo.emplace_back(binding_body(e), offset + 1);
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todo.emplace_back(binding_domain(e), offset);
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goto begin_loop;
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}
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}
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}
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}
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