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>
69 lines
2.7 KiB
C++
69 lines
2.7 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 <tuple>
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#include "util/interrupt.h"
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#include "kernel/replace_visitor.h"
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namespace lean {
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expr replace_visitor::visit_sort(expr const & e) { lean_assert(is_sort(e)); return e; }
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expr replace_visitor::visit_var(expr const & e) { lean_assert(is_var(e)); return e; }
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expr replace_visitor::visit_constant(expr const & e) { lean_assert(is_constant(e)); return e; }
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expr replace_visitor::visit_mlocal(expr const & e) {
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lean_assert(is_mlocal(e));
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return update_mlocal(e, visit(mlocal_type(e)));
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}
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expr replace_visitor::visit_meta(expr const & e) { return visit_mlocal(e); }
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expr replace_visitor::visit_local(expr const & e) { return visit_mlocal(e); }
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expr replace_visitor::visit_app(expr const & e) {
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lean_assert(is_app(e));
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return update_app(e, visit(app_fn(e)), visit(app_arg(e)));
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}
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expr replace_visitor::visit_binding(expr const & e) {
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lean_assert(is_binding(e));
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expr new_d = visit(binding_domain(e));
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expr new_b = visit(binding_body(e));
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return update_binding(e, new_d, new_b);
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}
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expr replace_visitor::visit_lambda(expr const & e) { return visit_binding(e); }
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expr replace_visitor::visit_pi(expr const & e) { return visit_binding(e); }
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expr replace_visitor::visit_macro(expr const & e) {
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lean_assert(is_macro(e));
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buffer<expr> new_args;
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for (unsigned i = 0; i < macro_num_args(e); i++)
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new_args.push_back(visit(macro_arg(e, i)));
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return update_macro(e, new_args.size(), new_args.data());
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}
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expr replace_visitor::save_result(expr const & e, expr && r, bool shared) {
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if (shared)
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m_cache.insert(std::make_pair(e, r));
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return r;
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}
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expr replace_visitor::visit(expr const & e) {
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check_system("expression replacer");
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bool shared = false;
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if (is_shared(e)) {
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shared = true;
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auto it = m_cache.find(e);
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if (it != m_cache.end())
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return it->second;
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}
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switch (e.kind()) {
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case expr_kind::Sort: return save_result(e, visit_sort(e), shared);
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case expr_kind::Macro: return save_result(e, visit_macro(e), shared);
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case expr_kind::Constant: return save_result(e, visit_constant(e), shared);
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case expr_kind::Var: return save_result(e, visit_var(e), shared);
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case expr_kind::Meta: return save_result(e, visit_meta(e), shared);
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case expr_kind::Local: return save_result(e, visit_local(e), shared);
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case expr_kind::App: return save_result(e, visit_app(e), shared);
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case expr_kind::Lambda: return save_result(e, visit_lambda(e), shared);
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case expr_kind::Pi: return save_result(e, visit_pi(e), shared);
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}
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lean_unreachable(); // LCOV_EXCL_LINE
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}
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}
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