eval_letrec_c

Synopsis

template <class Name, class Exp, class Body>
struct eval_letrec_c
{
  // unspecified
};

Description

The same as eval_letrec, but Exp and Body are angle-bracket expressions and not syntaxes.

Header

#include <mpllibs/metamonad/eval_letrec_c.hpp>

Expression semantics

For any n, e and b classes

eval_letrec_c<n, e, b>::type

is equivalent to

eval_letrec<n, syntax<e>, syntax<b>>::type

Example

using boost::mpl::times;
using boost::mpl::plus;
using boost::mpl::minus;
using boost::mpl::int_;
using boost::mpl::equal_to;

struct fact;

typedef
  eval_letrec_c<
    fact,
    lambda_c<
      n,
      if_<
        equal_to<n, int_<0>>,
        int_<1>,
        lazy<times<apply<fact, minus<n, int_<1>>>, n>>
      >
    >,
    lazy<apply<fact, int_<3>>>
  >::type
  fact_3;

Copyright Abel Sinkovics (abel at elte dot hu) 2011. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt

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