Re: [Boost-users] Lambda expressions

From: Lucio Flores (dogboy_l_at_[hidden])
Date: 2006-05-09 14:01:32

--- David Abrahams <dave_at_[hidden]> wrote:

> Lucio Flores <dogboy_l_at_[hidden]> writes:
> 
> > --- David Abrahams <dave_at_[hidden]> wrote:
> >
> >> Lucio Flores <dogboy_l_at_[hidden]> writes:
> >> 
> >> > I posted this question a few months ago, but I got pulled away to deal
> with
> >> > more pressing work issues. So here it goes again:
> >> >
> >> > I'm trying to use lambda expressions to implement 'twice'. So I came up
> >> with
> >> >
> >> >
> >> > typedef mpl::apply<_1, mpl::apply<_1, _2> > lambda_type;
> >> >
> >> > typedef lambda_type<boost::add_pointer<_1>, int> result_type;
> >> 
> >> Surely that doesn't compile(?)  lambda_type is a type; you can't follow
> >> it with a template argument list.
> >> 
> >
> > You're right!  .... But it did compile.... 
> 
> What compiler ate that without complaint?

gcc version 3.3.5 20050117 (prerelease) (SUSE Linux 9.3)

But the following wont compile:

typedef mpl::apply<_1, mpl::apply<_1, _2> > lambda_type;
typedef mpl::apply<lambda_type, boost::add_pointer<_1>, int>::type answer_type;

prog_3_6.cpp:22: error: no class template named `apply' in `struct lambda_type'
prog_3_6.cpp:22: error: syntax error before `;' token

-------------------------------------------

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