60 lines
1.9 KiB
C++
60 lines
1.9 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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#pragma once
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#include "kernel/expr_maps.h"
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#include "kernel/replace_fn.h"
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#include "kernel/context.h"
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namespace lean {
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/**
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\brief Base class for implementing operations that apply modifications
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an expressions.
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The default behavior is a NOOP, users must create subclasses and
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redefine the visit_* methods.
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This is a more expensive (and flexible) version of replace_fn in
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the file kernel/replace.h
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*/
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class replace_visitor {
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protected:
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typedef expr_map<expr> cache;
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cache m_cache;
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context m_ctx;
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expr save_result(expr const & e, expr && r, bool shared);
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virtual expr visit_type(expr const &, context const &);
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virtual expr visit_value(expr const &, context const &);
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virtual expr visit_constant(expr const &, context const &);
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virtual expr visit_var(expr const &, context const &);
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virtual expr visit_metavar(expr const &, context const &);
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virtual expr visit_app(expr const &, context const &);
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virtual expr visit_eq(expr const &, context const &);
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virtual expr visit_abst(expr const &, context const &);
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virtual expr visit_lambda(expr const &, context const &);
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virtual expr visit_pi(expr const &, context const &);
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virtual expr visit_let(expr const &, context const &);
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virtual expr visit(expr const &, context const &);
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optional<expr> visit(optional<expr> const &, context const &);
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void set_ctx(context const & ctx) {
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if (!is_eqp(m_ctx, ctx)) {
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m_ctx = ctx;
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m_cache.clear();
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}
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}
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public:
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expr operator()(expr const & e, context const & ctx = context()) {
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set_ctx(ctx);
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return visit(e, ctx);
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}
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void clear() {
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m_ctx = context();
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m_cache.clear();
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}
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};
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}
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