Re: [Boost-users] [Proto] Failed to Mimic the "Lazy Vector" Example

Subject: Re: [Boost-users] [Proto] Failed to Mimic the "Lazy Vector" Example
From: Thomas Heller (thom.heller_at_[hidden])
Date: 2010-12-08 14:47:34

Hossein Haeri wrote:

> Dear all,
> Trying to mimic what comes in the Lazy Vector example
> 
http://www.boost.org/doc/libs/1_45_0/doc/html/proto/users_guide.html#boost_proto.users_guide.examples
> I get a strange error speaking about result_of and the like. My guess is
> that there is some specialisation of a function object which does do the
> job for std::vector<> that I need to also specialise for my class. I can't
> find any track of that thing though. And, I might be totally wrong too...
> Anyway, for your reference, I have put the code as well as the error
> message that I get in GCC 4.5.1, MinGW, WinXP, SP3 in the PS section of
> this posting. Any ideas please?

The type EmtDomain is incomplete when it is used in EmtExpr (proto::extends 
...). The solution is to forward declare EmtExpr, define the Domain and then 
define the expression wrapper.

> TIA,--Hossein <Code>
> #include <iostream>
> 
> #include <boost/proto/proto.hpp>
> 
> namespace mpl = boost::mpl;
> namespace proto = boost::proto;
> using proto::_;
> 
> struct EWBase {};
> typedef proto::terminal<double (*) (double)> FunctionType;
> 
> struct EmtGrammar:
> proto::or_
> <
> proto::terminal<EWBase>,
> proto::shift_right<EmtGrammar, FunctionType>
>   >
> {};
> 
> struct EmtDomain;
> 
> template<typename Expr>
> struct EmtExpr
>   : proto::extends<Expr, EmtExpr<Expr>, EmtDomain>
> {
>     typedef proto::extends<Expr, EmtExpr<Expr>, EmtDomain> base_type;
> 
>     EmtExpr( Expr const & expr = Expr() )
>       : base_type( expr )
>     {}
> };
> 
> template< typename T >
> struct Emt
>   : EmtExpr<typename proto::terminal<EWBase>::type>
> {
>     typedef typename proto::terminal<EWBase>::type expr_type;
> 
>     Emt(): EmtExpr<expr_type>(expr_type::make(EWBase())) {}
> };
> 
> struct EmtDomain
>   : proto::domain<proto::generator<EmtExpr>, EmtGrammar>
> {};
> 
> int main()
> {
> return 0;
> }
> 
> </Code>
> <Error Message>
> 
> -------------- Build: Debug in ProtoGame2 ---------------
> 
> Compiling: main.cpp
> In file included from
> D:\Sources\Boost\boost_1_42_0/boost/proto/traits.hpp:34:0,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/expr.hpp:27,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/core.hpp:17,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/proto.hpp:12,
>                  from D:\My Documents\My
>                  Programmes\Tutorial\Proto\ProtoGame2\main.cpp:3:
> D:\Sources\Boost\boost_1_42_0/boost/utility/result_of.hpp: In
> instantiation of 'boost::detail::result_of_nested_result<EmtDomain,
> EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> boost::proto::argsns_::list1<const
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>)>':
> D:\Sources\Boost\boost_1_42_0/boost/utility/result_of.hpp:75:1:  
> instantiated from 'boost::detail::result_of_impl<EmtDomain,
> EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> boost::proto::argsns_::list1<const
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>), false>'
> D:
\Sources\Boost\boost_1_42_0/boost/utility/detail/result_of_iterate.hpp:24:109:
>   instantiated from
> 
'boost::result_of<EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> boost::proto::argsns_::list1<const
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>)>'
> D:
\Sources\Boost\boost_1_42_0/boost/preprocessor/iteration/detail/local.hpp:34:1:
>   instantiated from
> 
'boost::proto::exprns_::extends<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l>,
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >, EmtDomain, 0l>'
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:25:1:  
> instantiated from
> 'EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >'
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:36:1:  
> instantiated from here
> D:\Sources\Boost\boost_1_42_0/boost/utility/result_of.hpp:68:1: error:
> invalid use of incomplete type 'struct EmtDomain' D:\My Documents\My
> Programmes\Tutorial\Proto\ProtoGame2\main.cpp:20:8: error: forward
> declaration of 'struct EmtDomain' In file included from
> D:\Sources\Boost\boost_1_42_0/boost/proto/extends.hpp:533:0,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/core.hpp:23,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/proto.hpp:12,
>                  from D:\My Documents\My
>                  Programmes\Tutorial\Proto\ProtoGame2\main.cpp:3:
> D:
\Sources\Boost\boost_1_42_0/boost/preprocessor/iteration/detail/local.hpp:
> In instantiation of
> 
'boost::proto::exprns_::extends<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l>,
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >, EmtDomain, 0l>':
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:25:1:  
> instantiated from
> 'EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >'
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:36:1:  
> instantiated from here
> D:
\Sources\Boost\boost_1_42_0/boost/preprocessor/iteration/detail/local.hpp:34:1:
> error: no type named 'type' in 'struct
> 
boost::result_of<EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> boost::proto::argsns_::list1<const
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>)>' In file included from
> D:\Sources\Boost\boost_1_42_0/boost/proto/traits.hpp:34:0,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/expr.hpp:27,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/core.hpp:17,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/proto.hpp:12,
>                  from D:\My Documents\My
>                  Programmes\Tutorial\Proto\ProtoGame2\main.cpp:3:
> D:\Sources\Boost\boost_1_42_0/boost/utility/result_of.hpp: In
> instantiation of 'boost::detail::result_of_nested_result<EmtDomain,
> EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> 
boost::proto::argsns_::list1<EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>)>':
> D:\Sources\Boost\boost_1_42_0/boost/utility/result_of.hpp:75:1:  
> instantiated from 'boost::detail::result_of_impl<EmtDomain,
> EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> 
boost::proto::argsns_::list1<EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>), false>'
> D:
\Sources\Boost\boost_1_42_0/boost/utility/detail/result_of_iterate.hpp:24:109:
>   instantiated from
> 
'boost::result_of<EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> 
boost::proto::argsns_::list1<EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>)>'
> D:
\Sources\Boost\boost_1_42_0/boost/preprocessor/iteration/detail/local.hpp:34:1:
>   instantiated from
> 
'boost::proto::exprns_::extends<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l>,
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >, EmtDomain, 0l>'
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:25:1:  
> instantiated from
> 'EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >'
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:36:1:  
> instantiated from here
> D:\Sources\Boost\boost_1_42_0/boost/utility/result_of.hpp:68:1: error:
> invalid use of incomplete type 'struct EmtDomain' D:\My Documents\My
> Programmes\Tutorial\Proto\ProtoGame2\main.cpp:20:8: error: forward
> declaration of 'struct EmtDomain' In file included from
> D:\Sources\Boost\boost_1_42_0/boost/proto/extends.hpp:533:0,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/core.hpp:23,
>                  from
>                  D:\Sources\Boost\boost_1_42_0/boost/proto/proto.hpp:12,
>                  from D:\My Documents\My
>                  Programmes\Tutorial\Proto\ProtoGame2\main.cpp:3:
> D:
\Sources\Boost\boost_1_42_0/boost/preprocessor/iteration/detail/local.hpp:
> In instantiation of
> 
'boost::proto::exprns_::extends<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l>,
> EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >, EmtDomain, 0l>':
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:25:1:  
> instantiated from
> 'EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >'
> D:\My Documents\My Programmes\Tutorial\Proto\ProtoGame2\main.cpp:36:1:  
> instantiated from here
> D:
\Sources\Boost\boost_1_42_0/boost/preprocessor/iteration/detail/local.hpp:34:1:
> error: no type named 'type' in 'struct
> 
boost::result_of<EmtDomain(boost::proto::exprns_::expr<boost::proto::tag::function,
> 
boost::proto::argsns_::list1<EmtExpr<boost::proto::exprns_::expr<boost::proto::tag::terminal,
> boost::proto::argsns_::term<EWBase>, 0l> >&>, 1l>)>' Process terminated
> with status 1 (0 minutes, 2 seconds) 6 errors, 0 warnings
>  
> </Error Message>