Re: [Boost-users] [Proto] Building a mpl::vector from an expression

Subject: Re: [Boost-users] [Proto] Building a mpl::vector from an expression
From: christophe henry (henry_christophe_at_[hidden])
Date: 2009-08-20 10:33:06

Eric Niebler wrote:

> #include 
> #include 
> #include 
> #include 
> #include 
> #include 
> namespace proto = boost::proto; 
> namespace mpl = boost::mpl; 
> using proto::_; 
> 
> namespace My 
> { 
> struct my_tag {}; 
> 
> template 
> struct attribute_ 
> { 
> BOOST_PROTO_BASIC_EXTENDS( 
> proto::terminal::type 
> , attribute_ 
> , proto::default_domain 
> ) 
> }; 
> 
> attribute_<> const attribute = {{}}; 
> 
> struct BuildAttributes 
> : proto::make< 
> mpl::pop_front< 
> proto::fold_tree< 
> _ 
> , mpl::vector0<>() 
> , mpl::push_back() 
> > 
> > 
> > 
> {}; 
> } 
> 
> int main() 
> { 
> mpl::vector3 x = 
> My::BuildAttributes()( 
> My::attribute << int() << std::string() << bool() 
> ); 
> } 
> 
> HTH, 

 

Hi Eric,

 

It does! It is way more elegant than what I came up with.

I can even add a few features (like an optional end) inside and it still compiles much faster.

 

Thanks a lot,

 

Christophe

 

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