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feat(library): add new coercion API

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
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Leonardo de Moura 2014-05-15 16:48:47 -07:00
parent e79e0302d0
commit 2e3ffea2ec
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src/library/coercion.h Normal file
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/*
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/environment.h"
namespace lean {
/**
\brief Add an new coercion in the given environment.
There are three kinds of coercions supported
1- From type C to type D
type of f must have the form:
{l1 ... lk} Pi (x1 : A1) ... (xn : An) (y: C.{l1 ... lk} x1 ... xn), D.{L1 ... Lr} t1 ... tm
- C and D are constants.
- l1 ... lk are universe level parameters
- L1 ... Lr are universe level expressions
- t1 ... tm are level expressions
2- From type to sort
type of f must have the form:
{l1 ... lk} Pi (x1 : A1) ... (xn : An) (y: C.{l1 ... lk} x1 ... xn) (x : A), B
3- From type to function type
type of f must have the form:
{l1 ... lk} Pi (x1 : A1) ... (xn : An) (y: C.{l1 ... lk} x1 ... xn), Type.{L}
\pre \c f is a constant defined in \c env.
*/
environment add_coercion(environment const & env, expr const & f);
bool is_coercion(environment const & env, expr const & f);
list<expr_pair> get_coercions(environment const & env, expr const & from, expr const & from_type);
optional<expr> get_coercion(environment const & env, expr const & from, expr const & from_type, expr const & to_type);
optional<expr> get_coercion_to_sort(environment const & env, expr const & from, expr const & from_type);
optional<expr> get_coercion_to_fun(environment const & env, expr const & from, expr const & from_type);
}