6ada62a3ee
Motivation: prevent changes in the scalar fields layout from breaking C++ code. Ideally, we should do that for all constructors, and implement a tool that creates the C++ functions automatically for us. We don't do it because we will delete most of this code after we finish the Lean4 transition.
63 lines
2.8 KiB
C++
63 lines
2.8 KiB
C++
/*
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Copyright (c) 2015 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/environment.h"
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namespace lean {
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/** \brief Auxiliary information attached to projections. This information
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is used to simplify projection over constructor (efficiently).
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That is, given a projection pr_i associated with the constructor mk
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where A are parameters, we want to implement the following reduction
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efficiently. The idea is to avoid unfolding pr_i.
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pr_i A (mk A f_1 ... f_n) ==> f_i
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We also use this information in the rewriter/simplifier.
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*/
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class projection_info : public object_ref {
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public:
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projection_info(name const & c, unsigned nparams, unsigned i, bool inst_implicit);
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projection_info():projection_info(name(), 0, 0, false) {}
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projection_info(projection_info const & other):object_ref(other) {}
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projection_info(projection_info && other):object_ref(other) {}
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/* low-level constructors */
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explicit projection_info(object * o):object_ref(o) {}
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explicit projection_info(b_obj_arg o, bool b):object_ref(o, b) {}
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explicit projection_info(object_ref const & o):object_ref(o) {}
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projection_info & operator=(projection_info const & other) { object_ref::operator=(other); return *this; }
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projection_info & operator=(projection_info && other) { object_ref::operator=(other); return *this; }
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name const & get_constructor() const { return static_cast<name const &>(cnstr_get_ref(*this, 0)); }
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unsigned get_nparams() const { return static_cast<nat const &>(cnstr_get_ref(*this, 1)).get_small_value(); }
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unsigned get_i() const { return static_cast<nat const &>(cnstr_get_ref(*this, 2)).get_small_value(); }
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bool is_inst_implicit() const;
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};
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/** \brief Mark \c p as a projection in the given environment and store that
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\c mk is the constructor associated with it, \c nparams is the number of parameters, and
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\c i says that \c p is the i-th projection.
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*/
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environment save_projection_info(environment const & env, name const & p, name const & mk, unsigned nparams, unsigned i,
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bool inst_implicit);
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/** \brief If \c p is a projection in the given environment, then return the information
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associated with it (constructor, number of parameters, and index).
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If \c p is not a projection, then return nullptr.
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*/
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optional<projection_info> get_projection_info(environment const & env, name const & p);
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inline bool is_projection(environment const & env, name const & n) {
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return static_cast<bool>(get_projection_info(env, n));
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}
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/** \brief Return true iff the type named \c S can be viewed as
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a structure in the given environment.
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If not, generate an error message using \c pos.
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*/
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bool is_structure_like(environment const & env, name const & S);
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}
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