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Boost-Commit : |
From: eric_at_[hidden]
Date: 2008-04-28 16:51:36
Author: eric_niebler
Date: 2008-04-28 16:51:36 EDT (Mon, 28 Apr 2008)
New Revision: 44859
URL: http://svn.boost.org/trac/boost/changeset/44859
Log:
move lambda.cpp to mini_lambda.cpp
Added:
branches/proto/v4/libs/proto/example/mini_lambda.cpp
- copied unchanged from r44724, /branches/proto/v4/libs/proto/example/lambda.cpp
Removed:
branches/proto/v4/libs/proto/example/lambda.cpp
Text files modified:
branches/proto/v4/libs/proto/doc/examples.qbk | 2 +-
branches/proto/v4/libs/proto/example/Jamfile.v2 | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
Modified: branches/proto/v4/libs/proto/doc/examples.qbk
==============================================================================
--- branches/proto/v4/libs/proto/doc/examples.qbk (original)
+++ branches/proto/v4/libs/proto/doc/examples.qbk 2008-04-28 16:51:36 EDT (Mon, 28 Apr 2008)
@@ -17,7 +17,7 @@
[import ../example/vector.cpp]
[import ../example/map_assign.cpp]
[import ../example/futures.cpp]
-[import ../example/lambda.cpp]
+[import ../example/mini_lambda.cpp]
[/===============]
[section Examples]
Modified: branches/proto/v4/libs/proto/example/Jamfile.v2
==============================================================================
--- branches/proto/v4/libs/proto/example/Jamfile.v2 (original)
+++ branches/proto/v4/libs/proto/example/Jamfile.v2 2008-04-28 16:51:36 EDT (Mon, 28 Apr 2008)
@@ -63,8 +63,8 @@
map_assign.cpp
;
-exe lambda
+exe mini_lambda
:
- lambda.cpp
+ mini_lambda.cpp
;
Deleted: branches/proto/v4/libs/proto/example/lambda.cpp
==============================================================================
--- branches/proto/v4/libs/proto/example/lambda.cpp 2008-04-28 16:51:36 EDT (Mon, 28 Apr 2008)
+++ (empty file)
@@ -1,232 +0,0 @@
-//[ Lambda
-///////////////////////////////////////////////////////////////////////////////
-// 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 builds a simple but functional lambda library using Proto.
-
-#include <iostream>
-#include <algorithm>
-#include <boost/mpl/int.hpp>
-#include <boost/mpl/min_max.hpp>
-#include <boost/mpl/eval_if.hpp>
-#include <boost/mpl/identity.hpp>
-#include <boost/mpl/next_prior.hpp>
-#include <boost/fusion/tuple.hpp>
-#include <boost/typeof/typeof.hpp>
-#include <boost/typeof/std/ostream.hpp>
-#include <boost/typeof/std/iostream.hpp>
-#include <boost/proto/core.hpp>
-#include <boost/proto/context.hpp>
-#include <boost/proto/transform.hpp>
-namespace mpl = boost::mpl;
-namespace proto = boost::proto;
-namespace fusion = boost::fusion;
-using proto::_;
-
-// Forward declaration of the lambda expression wrapper
-template<typename T>
-struct lambda;
-
-struct lambda_domain
- : proto::domain<proto::pod_generator<lambda> >
-{};
-
-template<typename I>
-struct placeholder
-{
- typedef I arity;
-};
-
-template<typename T>
-struct placeholder_arity
-{
- typedef typename T::arity type;
-};
-
-// The lambda grammar, with the transforms for calculating the max arity
-struct Lambda
- : proto::or_<
- proto::when<
- proto::terminal< placeholder<_> >
- , mpl::next<placeholder_arity<proto::_value> >()
- >
- , proto::when< proto::terminal<_>
- , mpl::int_<0>()
- >
- , proto::when<
- proto::nary_expr<_, proto::vararg<_> >
- , proto::fold<_, mpl::int_<0>(), mpl::max<Lambda,proto::_state>()>
- >
- >
-{};
-
-// simple wrapper for calculating a lambda expression's arity.
-template<typename Expr>
-struct lambda_arity
- : boost::result_of<Lambda(Expr, mpl::void_, mpl::void_)>
-{};
-
-// The lambda context is the same as the default context
-// with the addition of special handling for lambda placeholders
-template<typename Tuple>
-struct lambda_context
- : proto::callable_context<lambda_context<Tuple> const>
-{
- lambda_context(Tuple const &args)
- : args_(args)
- {}
-
- template<typename Sig>
- struct result;
-
- template<typename This, typename I>
- struct result<This(proto::tag::terminal, placeholder<I> const &)>
- : fusion::result_of::at<Tuple, I>
- {};
-
- template<typename I>
- typename fusion::result_of::at<Tuple, I>::type
- operator ()(proto::tag::terminal, placeholder<I> const &) const
- {
- return fusion::at<I>(this->args_);
- }
-
- Tuple args_;
-};
-
-// The lambda<> expression wrapper makes expressions polymorphic
-// function objects
-template<typename T>
-struct lambda
-{
- BOOST_PROTO_BASIC_EXTENDS(T, lambda<T>, lambda_domain)
- BOOST_PROTO_EXTENDS_ASSIGN()
- BOOST_PROTO_EXTENDS_SUBSCRIPT()
-
- // Careful not to evaluate the return type of the nullary function
- // unless we have a nullary lambda!
- typedef typename mpl::eval_if<
- typename lambda_arity<T>::type
- , mpl::identity<void>
- , proto::result_of::eval<T const, lambda_context<fusion::tuple<> > >
- >::type nullary_type;
-
- // Define our operator () that evaluates the lambda expression.
- nullary_type operator ()() const
- {
- fusion::tuple<> args;
- lambda_context<fusion::tuple<> > ctx(args);
- return proto::eval(*this, ctx);
- }
-
- template<typename A0>
- typename proto::result_of::eval<T const, lambda_context<fusion::tuple<A0 const &> > >::type
- operator ()(A0 const &a0) const
- {
- fusion::tuple<A0 const &> args(a0);
- lambda_context<fusion::tuple<A0 const &> > ctx(args);
- return proto::eval(*this, ctx);
- }
-
- template<typename A0, typename A1>
- typename proto::result_of::eval<T const, lambda_context<fusion::tuple<A0 const &, A1 const &> > >::type
- operator ()(A0 const &a0, A1 const &a1) const
- {
- fusion::tuple<A0 const &, A1 const &> args(a0, a1);
- lambda_context<fusion::tuple<A0 const &, A1 const &> > ctx(args);
- return proto::eval(*this, ctx);
- }
-};
-
-// Define some lambda placeholders
-lambda<proto::terminal<placeholder<mpl::int_<0> > >::type> const _1 = {{}};
-lambda<proto::terminal<placeholder<mpl::int_<1> > >::type> const _2 = {{}};
-
-template<typename T>
-lambda<typename proto::terminal<T>::type> const val(T const &t)
-{
- lambda<typename proto::terminal<T>::type> that = {{t}};
- return that;
-}
-
-template<typename T>
-lambda<typename proto::terminal<T &>::type> const var(T &t)
-{
- lambda<typename proto::terminal<T &>::type> that = {{t}};
- return that;
-}
-
-template<typename T>
-struct construct_helper
-{
- typedef T result_type; // for TR1 result_of
-
- T operator()() const
- { return T(); }
-
- template<typename A0>
- T operator()(A0 const &a0) const
- { return T(a0); }
-
- template<typename A0, typename A1>
- T operator()(A0 const &a0, A1 const &a1) const
- { return T(a0, a1); }
-};
-
-// Generate BOOST_PROTO_MAX_ARITY-1 overloads of the
-// construct function template like the one defined above.
-BOOST_PROTO_DEFINE_VARARG_FUNCTION_TEMPLATE( \
- construct \
- , lambda_domain \
- , (proto::tag::function) \
- , ((construct_helper)(typename)) \
-)
-
-struct S
-{
- S() {}
- S(int i, char c)
- {
- std::cout << "S(" << i << "," << c << ")\n";
- }
-};
-
-int main()
-{
- // Create some lambda objects and immediately
- // invoke them by applying their operator():
- int i = ( (_1 + 2) / 4 )(42);
- std::cout << i << std::endl; // prints 11
-
- int j = ( (-(_1 + 2)) / 4 )(42);
- std::cout << j << std::endl; // prints -11
-
- double d = ( (4 - _2) * 3 )(42, 3.14);
- std::cout << d << std::endl; // prints 2.58
-
- // check non-const ref terminals
- (std::cout << _1 << " -- " << _2 << '\n')(42, "Life, the Universe and Everything!");
- // prints "42 -- Life, the Universe and Everything!"
-
- // "Nullary" lambdas work too
- int k = (val(1) + val(2))();
- std::cout << k << std::endl; // prints 3
-
- // check array indexing for kicks
- int integers[5] = {0};
- (var(integers)[2] = 2)();
- (var(integers)[_1] = _1)(3);
- std::cout << integers[2] << std::endl; // prints 2
- std::cout << integers[3] << std::endl; // prints 3
-
- // Now use a lambda with an STL algorithm!
- int rgi[4] = {1,2,3,4};
- char rgc[4] = {'a','b','c','d'};
- S rgs[4];
-
- std::transform(rgi, rgi+4, rgc, rgs, construct<S>(_1, _2));
- return 0;
-}
-//]
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