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Subject: Re: [boost] determine first arg of callable
From: Peter Dimov (lists_at_[hidden])
Date: 2013-05-15 11:59:46
This still doesn't quite explain it. Let's say that my fn takes a
std::string. How does D know what string to pass? An empty string? "foo"?
"hello world"? Where does the argument value come from?
-----Original Message-----
From: Oliver Kowalke
Sent: Wednesday, May 15, 2013 18:52
To: boost
Subject: Re: [boost] determine first arg of callable
013/5/15 Peter Dimov <lists_at_[hidden]>
> You've omitted the only interesting part.
template< typename Arg >
struct Q {...};
struct B
{
virtual void run() = 0;
};
template< typename Fn, typename Arg >
struct D : public B
{
Fn fn;
D( Fn fn_) : fn( fn_) {}
void run() {
Q< Arg > q;
fn( q)
} // argument construction omitted
};
struct X
{
B * b;
template< typename Fn >
X( Fn fn) : b( 0)
{
typedef typename Magic< Fn >::arg1_type arg_type;
b = new D< Fn, arg_type >( fn);
}
void run() { b->run(); }
};
I want to construct a Q<> in D::run() and pass it to fn.
Magic<> can be specialized for raw function pointers, function<> etc.
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