A functor-based curry: YET I HAVE PROBLEM

[downs]

Im, Jihyuk wrote:
> thanx for your kind reply :)
> 
> now I get to know the problem was a function template block should has one 
> definition inside.
> but I think if the second code works fine, I think it's useful for
> listing template parameter once and use various tempalte declaration but the 
> parameter deduced with parameters to
> template function inside.
> 
> Indeed my third code works fine for me :) your code contains string code
> evaluation and mixin that's yet tough to me as c++ programmer
> 
> But i found this simple code also emits duduction failure error
> 
> [code]
> template Foo( R, A, U  )

Here's your problem. Since A and U are each single template parameters, they can each assume precisely _one_ type.
However, if you'll look, &plus_3 is a void delegate(int, int, int).
This means that A'd have to be int, U also, and ... then we still got an int left over that doesn't fit the template description.
U... fixes this because it's a tuple and tuples can assume an arbitrary number of types.

> {
>  R delegate (U)  Foo( R delegate ( A, U ) dg, A a )
>  {
>   R Foo_( U u )
>   { R i; return i; }
>   return &Foo2_;
>  }
> }
> 
> void my_test()
> {
>  int plus_3( int a, int b, int c )
>  {
>   return a+b+c;
>  }
> 
>  Foo( &plus_3, 10 );  // deduction failure
> }
> [/code]
> 

 --downs