80 lines
2.7 KiB
C++
80 lines
2.7 KiB
C++
/*
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Copyright (c) 2013-2014 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/lua.h"
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#include "util/list.h"
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#include "util/name.h"
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#include "kernel/formatter.h"
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#include "kernel/environment.h"
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#include "library/io_state_stream.h"
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namespace lean {
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/**
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\brief A goal is just encoding the synthesis problem <tt>(?m l_1 .... l_n) : t</tt>
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That is, we want to find a term \c ?m s.t. <tt>(?m l_1 ... l_n)</tt> has type \c t
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The terms \c l_i are just local constants.
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We can convert any metavariable
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<tt>?m : Pi (x_1 : A_1) ... (x_n : A_n[x_1, ..., x_{n-1}]), B[x_1, ..., x_n]</tt>
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into a goal by simply creating the local constants
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<tt>l_1 : A_1, ..., l_n : A_n[l_1, ..., l_{n-1}]</tt>
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and then, create the goal
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<tt>?m l_1 ... l_n : B[l_1, ..., l_n]</tt>
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Now, suppose we find a term \c b with type <tt>B[l_1, ... l_n]</tt>, then we can simply
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find \c ?m by abstracting <tt>l_1, ..., l_n</tt>
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We can check whether a goal is well formed in an environment by type checking.
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*/
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class goal {
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expr m_meta;
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expr m_type;
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public:
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goal() {}
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goal(expr const & m, expr const & t):m_meta(m), m_type(t) {}
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expr const & get_meta() const { return m_meta; }
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expr const & get_type() const { return m_type; }
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name get_name() const { return mlocal_name(get_app_fn(m_meta)); }
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expr get_mvar() const { return get_app_fn(m_meta); }
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/**
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\brief Given a term \c v with type get_type(), build a lambda abstraction
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that is the solution for the metavariable associated with this goal.
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*/
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expr abstract(expr const & v) const;
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/**
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\brief Create a metavariable application <tt>(?m l_1 ... l_n)</tt> with the given type,
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and the locals from this goal. If <tt>only_contextual == true</tt>, then we only include
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the local constants that are marked as contextual.
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*/
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expr mk_meta(name const & m, expr const & type, bool only_contextual = true) const;
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/**
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brief Return true iff get_type() only contains local constants that arguments
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of get_meta(), and each argument of get_meta() only contains local constants
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that are previous arguments.
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*/
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bool validate_locals() const;
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/**
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\brief Return true iff \c validate_locals() return true and type of \c get_meta() in
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\c env is get_type()
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*/
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bool validate(environment const & env) const;
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format pp(environment const & env, formatter const & fmt, options const & opts) const;
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};
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io_state_stream const & operator<<(io_state_stream const & out, goal const & g);
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UDATA_DEFS(goal)
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void open_goal(lua_State * L);
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}
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