71 lines
2.7 KiB
C++
71 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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#pragma once
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#include <utility>
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#include "util/list.h"
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#include "kernel/expr.h"
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namespace lean {
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/**
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\brief An element of the Lean context.
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\see context
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*/
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class context_entry {
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name m_name;
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expr m_domain;
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expr m_body;
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public:
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context_entry(name const & n, expr const & d, expr const & b):m_name(n), m_domain(d), m_body(b) {}
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context_entry(name const & n, expr const & d):m_name(n), m_domain(d) {}
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name const & get_name() const { return m_name; }
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expr const & get_domain() const { return m_domain; }
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expr const & get_body() const { return m_body; }
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};
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/**
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\brief A context is essentially a mapping from free-variables to types (and definition/body).
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*/
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class context {
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list<context_entry> m_list;
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explicit context(list<context_entry> const & l):m_list(l) {}
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public:
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context() {}
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context(context const & c, name const & n, expr const & d):m_list(context_entry(n, d), c.m_list) {}
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context(context const & c, name const & n, expr const & d, expr const & b):m_list(context_entry(n, d, b), c.m_list) {}
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context_entry const & lookup(unsigned vidx) const;
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std::pair<context_entry const &, context> lookup_ext(unsigned vidx) const;
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bool empty() const { return is_nil(m_list); }
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operator bool() const { return !empty(); }
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unsigned size() const { return length(m_list); }
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typedef list<context_entry>::iterator iterator;
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iterator begin() const { return m_list.begin(); }
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iterator end() const { return m_list.end(); }
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friend bool is_eqp(context const & c1, context const & c2) { return is_eqp(c1.m_list, c2.m_list); }
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/**
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\brief Return a new context where the entries at positions [s, s+n) were removed.
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\pre size() >= s + n
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*/
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context remove(unsigned s, unsigned n) const;
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};
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/**
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\brief Return the context entry for the free variable with de
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Bruijn index \c i, and the context for this entry.
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*/
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inline std::pair<context_entry const &, context> lookup_ext(context const & c, unsigned i) { return c.lookup_ext(i); }
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/**
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\brief Return the context entry for the free variable with de
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Bruijn index \c i.
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*/
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inline context_entry const & lookup(context const & c, unsigned i) { return c.lookup(i); }
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inline context extend(context const & c, name const & n, expr const & d, expr const & b) { return context(c, n, d, b); }
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inline context extend(context const & c, name const & n, expr const & d) { return context(c, n, d); }
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inline bool empty(context const & c) { return c.empty(); }
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std::ostream & operator<<(std::ostream & out, context const & ctx);
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}
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