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Boost-Commit : |
Subject: [Boost-commit] svn:boost r76281 - trunk/libs/proto/example
From: eric_at_[hidden]
Date: 2012-01-02 16:27:19
Author: eric_niebler
Date: 2012-01-02 16:27:18 EST (Mon, 02 Jan 2012)
New Revision: 76281
URL: http://svn.boost.org/trac/boost/changeset/76281
Log:
simplify the BLL example using per-domain as_child
Text files modified:
trunk/libs/proto/example/lambda.hpp | 129 ++++++++++++---------------------------
1 files changed, 41 insertions(+), 88 deletions(-)
Modified: trunk/libs/proto/example/lambda.hpp
==============================================================================
--- trunk/libs/proto/example/lambda.hpp (original)
+++ trunk/libs/proto/example/lambda.hpp 2012-01-02 16:27:18 EST (Mon, 02 Jan 2012)
@@ -1,10 +1,17 @@
#ifndef BOOST_PP_IS_ITERATING
+ ///////////////////////////////////////////////////////////////////////////////
+ // Copyright 2008 Eric Niebler. 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)
+ //
+ // This example contains a full-featured reimplementation of the old,
+ // now-deprecated Boost Lambda Library (BLL) on top of Boost.Proto. It
+ // is necessarily complex to accomodate all the quirks and inconsistencies
+ // of that old library, but it is a good example of how to build a
+ // complete and full-featured EDLS using Proto.
#ifndef BOOST_LAMBDA_HPP_EAN_04_19_2008
#define BOOST_LAMBDA_HPP_EAN_04_19_2008
- #define BOOST_PROTO_MAX_ARITY 10
- #define BOOST_PROTO_MAX_FUNCTION_CALL_ARITY 5
-
#include <iosfwd>
#include <typeinfo>
#include <algorithm>
@@ -17,7 +24,6 @@
#include <boost/mpl/next_prior.hpp>
#include <boost/mpl/min_max.hpp>
#include <boost/mpl/assert.hpp>
- #include <boost/mpl/apply_wrap.hpp>
#include <boost/preprocessor.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/utility/result_of.hpp>
@@ -26,9 +32,6 @@
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/remove_const.hpp>
#include <boost/type_traits/is_same.hpp>
- #include <boost/type_traits/is_abstract.hpp>
- #include <boost/type_traits/is_array.hpp>
- #include <boost/type_traits/is_function.hpp>
#include <boost/proto/proto.hpp>
#ifndef BOOST_LAMBDA_MAX_ARITY
@@ -102,27 +105,6 @@
, proto::otherwise<proto::fold<proto::_, mpl::true_(), mpl::and_<proto::_state, IsNullary>()> >
>
{};
-
- struct at : proto::callable
- {
- template<class Sig>
- struct result;
-
- template<class This, class Cont, class Int>
- struct result<This(Cont, Int)>
- : fusion::result_of::at<
- typename remove_reference<Cont>::type
- , typename remove_reference<Int>::type
- >
- {};
-
- template<typename Cont, typename Int>
- typename fusion::result_of::at<Cont, Int>::type
- operator ()(Cont &cont, Int const &) const
- {
- return fusion::at<Int>(cont);
- }
- };
struct Eval;
@@ -268,7 +250,7 @@
{
template<typename Expr, typename State, typename Data, long Arity, typename BackTag>
struct impl2;
-
+
#define M0(Z, N, DATA) \
case proto::tag_of<typename proto::result_of::child_c<Expr, N>::type>::type::value: \
Eval()(proto::child_c<N>(expr), state, data); \
@@ -350,23 +332,23 @@
throw e;
}
};
-
+
struct unwrap_ref : proto::callable
{
template<typename Sig>
struct result;
-
+
template<typename This, typename T>
struct result<This(reference_wrapper<T>)>
{
- typedef T &type;
+ typedef T &type;
};
-
+
template<typename This, typename T>
struct result<This(T &)>
: result<This(T)>
{};
-
+
template<typename T>
T &operator()(reference_wrapper<T> const &ref) const
{
@@ -429,7 +411,7 @@
: proto::or_<
proto::when<
proto::terminal<placeholder<proto::_> >
- , at(proto::_data, proto::_value)
+ , proto::functional::at(proto::_data, proto::_value)
>
, proto::when<
proto::terminal<exception_placeholder>
@@ -490,58 +472,29 @@
using exprns_::llexpr;
- template<typename T>
- struct is_stream
- {
- private:
- static T &t;
- typedef char yes_type;
- typedef char (&no_type)[2];
- static no_type test_is_stream(...);
- template<typename Char, typename Traits>
- static yes_type test_is_stream(std::basic_istream<Char, Traits> &);
- template<typename Char, typename Traits>
- static yes_type test_is_stream(std::basic_ostream<Char, Traits> &);
- public:
- typedef bool value_type;
- static const bool value = sizeof(yes_type == sizeof(test_is_stream(t)));
- typedef mpl::bool_<value> type;
- };
-
- // These terminal types are always stored by reference
- template<typename Value>
- struct store_by_ref
- : mpl::or_<
- is_abstract<Value>
- , is_array<Value>
- , is_function<Value>
- , is_stream<Value>
- >
- {};
-
- // Wrap expressions in lambda::llexpr<>, and hold children nodes
- // and some terminal types by value.
+ // Wrap expressions in lambda::llexpr<>.
struct Generator
- : proto::or_<
- proto::when<
- proto::and_<
- proto::terminal<proto::_>
- , proto::if_<store_by_ref<proto::_value>()>
- >
- , proto::pod_generator<llexpr>(proto::_)
- >
- , proto::otherwise<
- proto::compose_generators<
- proto::by_value_generator
- , proto::pod_generator<llexpr>
- >(proto::_)
- >
- >
+ : proto::pod_generator<llexpr>
{};
+ // The domain for the lambda library. It
struct lldomain
- : proto::domain<Generator, Grammar>
- {};
+ : proto::domain<Generator, Grammar, proto::default_domain>
+ {
+ // Make all terminals and children held by value instead of by reference.
+ // Proto::domain<>::as_expr<> holds everything it can by value; the only
+ // exceptions are function types, abstract types, and iostreams.
+ template<typename T>
+ struct as_child
+ : proto_base_domain::as_expr<T>
+ {};
+
+ // The exception is arrays, which should still be held by reference
+ template<typename T, std::size_t N>
+ struct as_child<T[N]>
+ : proto_base_domain::as_child<T[N]>
+ {};
+ };
template<typename Sig>
struct llresult;
@@ -653,7 +606,7 @@
{
template<typename Sig>
struct result;
-
+
template<typename This, typename T>
struct result<This(T &)>
{
@@ -745,7 +698,7 @@
{
typedef llexpr<typename proto::terminal<T &>::type> type;
};
-
+
template<typename T>
llexpr<typename proto::terminal<T &>::type> const
var(T &t)
@@ -776,7 +729,7 @@
{
typedef llexpr<typename proto::terminal<T const &>::type> type;
};
-
+
template<typename T>
llexpr<typename proto::terminal<T const &>::type> const
constant_ref(T const &t)
@@ -1142,7 +1095,7 @@
{
return t;
}
-
+
#define M1(N, typename_A, A_const_ref, A_const_ref_a, ref_a) \
template<typename_A(N)> \
typename proto::result_of::make_expr< \
@@ -1741,7 +1694,7 @@
}
}}
-
+
namespace boost
{
template<typename Expr>
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