lean2/src/kernel/abstract.h
Leonardo de Moura 984c4149fa Add helper functions for creating Let expressions. Add simple type checking test for Let expressions.
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-08-14 22:30:12 -07:00

54 lines
2.7 KiB
C++

/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#pragma once
#include "expr.h"
namespace lean {
/**
\brief Replace the expressions s[0], ..., s[n-1] in e with var(n-1), ..., var(0).
Structural equality is used to compare subexpressions of e with the s[i]'s.
\pre s[0], ..., s[n-1] must be closed expressions (i.e., no free variables).
*/
expr abstract(expr const & e, unsigned n, expr const * s);
inline expr abstract(expr const & e, expr const & s) { return abstract(e, 1, &s); }
/**
\brief Replace the expressions s[0], ..., s[n-1] in e with var(n-1), ..., var(0).
Pointer comparison is used to compare subexpressions of e with the s[i]'s.
\pre s[0], ..., s[n-1] must be closed expressions (i.e., no free variables).
*/
expr abstract_p(expr const & e, unsigned n, expr const * s);
inline expr abstract_p(expr const & e, expr const & s) { return abstract_p(e, 1, &s); }
/**
\brief Create a lambda expression (lambda (x : t) b), the term b is abstracted using abstract(b, constant(x)).
*/
inline expr Fun(name const & n, expr const & t, expr const & b) { return mk_lambda(n, t, abstract(b, mk_constant(n))); }
inline expr Fun(expr const & n, expr const & t, expr const & b) { return mk_lambda(const_name(n), t, abstract(b, n)); }
inline expr Fun(std::pair<expr const &, expr const &> const & p, expr const & b) { return Fun(p.first, p.second, b); }
expr Fun(std::initializer_list<std::pair<expr const &, expr const &>> const & l, expr const & b);
/**
\brief Create a Pi expression (pi (x : t) b), the term b is abstracted using abstract(b, constant(x)).
*/
inline expr Pi(name const & n, expr const & t, expr const & b) { return mk_pi(n, t, abstract(b, mk_constant(n))); }
inline expr Pi(expr const & n, expr const & t, expr const & b) { return mk_pi(const_name(n), t, abstract(b, n)); }
inline expr Pi(std::pair<expr const &, expr const &> const & p, expr const & b) { return Pi(p.first, p.second, b); }
expr Pi(std::initializer_list<std::pair<expr const &, expr const &>> const & l, expr const & b);
/**
\brief Create a Let expression (Let x := v in b), the term b is abstracted using abstract(b, x).
*/
inline expr Let(name const & x, expr const & v, expr const & b) { return mk_let(x, v, abstract(b, mk_constant(x))); }
inline expr Let(expr const & x, expr const & v, expr const & b) { return mk_let(const_name(x), v, abstract(b, x)); }
inline expr Let(std::pair<expr const &, expr const &> const & p, expr const & b) { return Let(p.first, p.second, b); }
expr Let(std::initializer_list<std::pair<expr const &, expr const &>> const & l, expr const & b);
}