easily convert any method/function to a delegate

[Daniel Korsgaard]

BCS wrote:
> Daniel Korsgaard wrote:
>> two simple function templates that together will enable you to 
>> mindlessly use delegates everywhere.
>>
>> Whee first post on this NG :D
>> .. hope you like it..
>>
>> -------------------
>>
> [...]
> 
>> /// two functions that will convert any
>> R delegate(P) to_delegate(R, P...)(R delegate(P) dg)
>> {
>>     // insanely advanced operation!
>>     return dg;
>> }
>>
>> /// ditto
>> R delegate(P) to_delegate(R, P...)(R function(P) fp)
>> {
>>     R delegate(P) dg;
>>     dg.funcptr = fp;
>>     dg.ptr = null;
>>     return dg;
>> }
> 
> 
> 
> IIRC that doesn't (quite) work because some functions pass an arg in the 
> same place as methods pass "this"

Bummer :(

> 
> However IIRC you /can/ pass the function pointer as the delegate ptr and 
> then have the delegate code convert it back to the correct type and call 
> it.

Aye ?!

> 
> R delegate(P) to_delegate(R, P...)(R function(P) fp)
> {
>     auto dg = delegate R(P p)
>         {return (cast(R function(P))(cast(void*)this))(p);}
>     dg.ptr = cast(void*)fp;
>     return dg;
> }

Err.. where do you get that 'this' from?

Anyways, my idea was to cut of the additional call. But if it really 
have to be there, this is a lot cleaner:

R delegate(P) to_delegate(R, P...)(R function(P) fp)
{
     return delegate R(P p) { return fp(p); };
}

.. hope you like it..