34 lines
1.4 KiB
C
34 lines
1.4 KiB
C
|
/*
|
||
|
|
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
|
||
|
|
Released under Apache 2.0 license as described in the file LICENSE.
|
||
|
|
|
||
|
|
Author: Leonardo de Moura
|
||
|
|
*/
|
||
|
|
#pragma once
|
||
|
|
#include "kernel/expr.h"
|
||
|
|
|
||
|
|
namespace lean {
|
||
|
|
/**
|
||
|
|
\brief The Lean kernel can be instantiated with different normalization extensions.
|
||
|
|
Each extension is part of the trusted code base. The extensions allow us to support
|
||
|
|
different flavors of the core type theory. We will use these extensions to implement
|
||
|
|
inductive datatype (ala Coq), HIT, record types, etc.
|
||
|
|
*/
|
||
|
|
class normalizer_extension {
|
||
|
|
public:
|
||
|
|
virtual ~normalizer_extension() {}
|
||
|
|
virtual optional<expr> operator()(expr const & e, extension_context & ctx) const = 0;
|
||
|
|
/** \brief Return true if the extension may reduce \c e after metavariables are instantiated. */
|
||
|
|
virtual bool may_reduce_later(expr const & e, extension_context & ctx) const = 0;
|
||
|
|
/** \brief Return true iff the extension supports a feature with the given name,
|
||
|
|
this method is only used for sanity checking. */
|
||
|
|
virtual bool supports(name const & feature) const = 0;
|
||
|
|
};
|
||
|
|
|
||
|
|
/** \brief Create the do-nothing normalizer extension */
|
||
|
|
std::unique_ptr<normalizer_extension> mk_id_normalizer_extension();
|
||
|
|
|
||
|
|
/** \brief Create the composition of two normalizer extensions */
|
||
|
|
std::unique_ptr<normalizer_extension> compose(std::unique_ptr<normalizer_extension> && ext1, std::unique_ptr<normalizer_extension> && ext2);
|
||
|
|
}
|