289 lines
10 KiB
C++
289 lines
10 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 <iostream>
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#include <memory>
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#include "kernel/context.h"
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#include "kernel/object.h"
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#include "kernel/level.h"
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namespace lean {
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/**
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\brief Lean environment for defining constants, inductive
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datatypes, universe variables, et.c
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*/
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class environment {
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private:
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struct imp;
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std::shared_ptr<imp> m_ptr;
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void check_type(name const & n, expr const & t, expr const & v);
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environment(std::shared_ptr<imp> const & parent, bool);
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explicit environment(std::shared_ptr<imp> const & ptr);
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friend class read_only_environment;
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friend class read_write_environment;
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public:
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environment();
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~environment();
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friend bool is_eqp(environment const & env1, environment const & env2) { return env1.m_ptr.get() == env2.m_ptr.get(); }
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// =======================================
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// Parent/Child environment management
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/**
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\brief Create a child environment. This environment will only allow "read-only" operations until
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all children environments are deleted.
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*/
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environment mk_child() const;
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/** \brief Return true iff this environment has children environments. */
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bool has_children() const;
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/** \brief Return true iff this environment has a parent environment. */
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bool has_parent() const;
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/**
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\brief Return parent environment of this environment.
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\pre has_parent()
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*/
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environment parent() const;
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// =======================================
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// =======================================
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// Universe variables
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/**
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\brief Add a new universe variable with name \c n and constraint <tt>n >= l</tt>.
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Return the new variable.
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\remark An exception is thrown if a universe inconsistency is detected.
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*/
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level add_uvar(name const & n, level const & l);
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level add_uvar(name const & n) { return add_uvar(n, level()); }
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/**
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\brief Return true iff the constraint l1 >= l2 is implied by the constraints
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in the environment.
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*/
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bool is_ge(level const & l1, level const & l2) const;
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/**
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\brief Return universal variable with the given name.
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Throw an exception if variable is not defined in this environment.
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*/
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level get_uvar(name const & n) const;
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// =======================================
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// =======================================
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// Environment Objects
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/**
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\brief Add builtin value to the environment.
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\pre is_value(v)
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*/
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void add_builtin(expr const & v);
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/**
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\brief Add a builtin value set to the environment.
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The set is registered by providing a representative of the set.
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Each builtin set of values is implemented by a C++ class.
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The environment will only accept object of the same class of
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the representative. This functionality is used to support
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infinite set of builtin values such as the natural numbers.
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\pre is_value(r);
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*/
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void add_builtin_set(expr const & r);
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/**
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\brief Add a new definition n : t := v.
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It throws an exception if v does not have type t.
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It throws an exception if there is already an object with the given name.
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If opaque == true, then definition is not used by normalizer.
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*/
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void add_definition(name const & n, expr const & t, expr const & v, bool opaque = false);
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void add_theorem(name const & n, expr const & t, expr const & v);
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/**
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\brief Add a new definition n : infer_type(v) := v.
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It throws an exception if there is already an object with the given name.
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If opaque == true, then definition is not used by normalizer.
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*/
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void add_definition(name const & n, expr const & v, bool opaque = false);
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/**
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\brief Add a new fact (Axiom or Fact) to the environment.
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It throws an exception if there is already an object with the given name.
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*/
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void add_axiom(name const & n, expr const & t);
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void add_var(name const & n, expr const & t);
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/**
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\brief Register the given unanymous object in this environment.
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The environment assume the object ownership.
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*/
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void add_neutral_object(neutral_object_cell * o);
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/**
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\brief Return the object with the given name.
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It throws an exception if the environment does not have an object with the given name.
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*/
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object const & get_object(name const & n) const;
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/**
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\brief Find a given object in the environment. Return the null
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object if there is no object with the given name.
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\remark Object implements operator bool(), and the null object returns false.
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*/
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object const & find_object(name const & n) const;
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/** \brief Return true iff the environment has an object with the given name */
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bool has_object(name const & n) const { return find_object(n); }
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/**
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\brief Return the type of \c e in the given context and this environment.
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*/
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expr infer_type(expr const & e, context const & ctx = context()) const;
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/**
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\brief Normalize \c e in the given context and this environment.
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*/
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expr normalize(expr const & e, context const & ctx = context()) const;
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/**
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\brief Low-level function for accessing objects. Consider using iterators.
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*/
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unsigned get_num_objects(bool local) const;
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/**
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\brief Low-level function for accessing objects. Consider using iterators.
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*/
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object const & get_object(unsigned i, bool local) const;
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/** \brief Iterator for Lean environment objects. */
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class object_iterator {
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environment const & m_env;
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unsigned m_idx;
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bool m_local;
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friend class environment;
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object_iterator(environment const & env, unsigned idx, bool local):m_env(env), m_idx(idx), m_local(local) {}
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public:
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object_iterator(object_iterator const & s):m_env(s.m_env), m_idx(s.m_idx), m_local(s.m_local) {}
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object_iterator & operator++() { ++m_idx; return *this; }
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object_iterator operator++(int) { object_iterator tmp(*this); operator++(); return tmp; }
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object_iterator & operator--() { --m_idx; return *this; }
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object_iterator operator--(int) { object_iterator tmp(*this); operator--(); return tmp; }
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bool operator==(object_iterator const & s) const { lean_assert(&m_env == &(s.m_env)); return m_idx == s.m_idx; }
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bool operator!=(object_iterator const & s) const { return !operator==(s); }
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object const & operator*() { return m_env.get_object(m_idx, m_local); }
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object const * operator->() { return &(m_env.get_object(m_idx, m_local)); }
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};
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/**
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\brief Return an iterator to the beginning of the sequence of
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objects stored in this environment.
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\remark The objects in this environment and ancestor
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environments are considered
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*/
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object_iterator begin_objects() const { return object_iterator(*this, 0, false); }
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/**
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\brief Return an iterator to the end of the sequence of
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objects stored in this environment.
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\remark The objects in this environment and ancestor
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environments are considered
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*/
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object_iterator end_objects() const { return object_iterator(*this, get_num_objects(false), false); }
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/**
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\brief Return an iterator to the beginning of the sequence of
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objects stored in this environment (objects in ancestor
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environments are ingored).
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*/
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object_iterator begin_local_objects() const { return object_iterator(*this, 0, true); }
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/**
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\brief Return an iterator to the end of the sequence of
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objects stored in this environment (objects in ancestor
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environments are ingored).
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*/
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object_iterator end_local_objects() const { return object_iterator(*this, get_num_objects(true), true); }
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// =======================================
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/** \brief Display universal variable constraints and objects stored in this environment and its parents. */
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void display(std::ostream & out) const;
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/**
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\brief Frontend can store data in environment extensions.
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Each extension is associated with a unique token/id.
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This token allows the frontend to retrieve/store an extension object
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in the environment
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*/
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class extension {
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friend struct imp;
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imp * m_env;
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unsigned m_extid; // extension id
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extension const * get_parent_core() const;
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public:
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extension();
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virtual ~extension();
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/**
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\brief Return a constant reference for a parent extension,
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and a nullptr if there is no parent/ancestor, or if the
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parent/ancestor has an extension.
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*/
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template<typename Ext> Ext const * get_parent() const {
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extension const * ext = get_parent_core();
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lean_assert(!ext || dynamic_cast<Ext const *>(ext) != nullptr);
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return static_cast<Ext const *>(ext);
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}
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};
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/**
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\brief Register an environment extension. Every environment
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object will contain this extension. The funciton mk creates a
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new instance of the extension. The extension object can be
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retrieved using the token (unsigned integer) returned by this
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method.
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\remark The extension objects are created on demand.
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\see get_extension
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*/
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typedef std::unique_ptr<extension> (*mk_extension)();
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static unsigned register_extension(mk_extension mk);
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private:
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extension const & get_extension_core(unsigned extid) const;
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extension & get_extension_core(unsigned extid);
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public:
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/**
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\brief Retrieve the extension associated with the token \c extid.
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The token is the value returned by \c register_extension.
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*/
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template<typename Ext>
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Ext const & get_extension(unsigned extid) const {
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extension const & ext = get_extension_core(extid);
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lean_assert(dynamic_cast<Ext const *>(&ext) != nullptr);
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return static_cast<Ext const &>(ext);
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}
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template<typename Ext>
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Ext & get_extension(unsigned extid) {
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extension & ext = get_extension_core(extid);
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lean_assert(dynamic_cast<Ext*>(&ext) != nullptr);
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return static_cast<Ext&>(ext);
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}
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public:
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typedef std::weak_ptr<imp> weak_ref;
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weak_ref to_weak_ref() const { return weak_ref(m_ptr); }
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environment(weak_ref const & r);
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};
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}
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