Convert a delegate to a function (i.e. make a thunk)

[David Nadlinger]

On Wednesday, 25 April 2012 at 21:27:30 UTC, Jonathan M Davis 
wrote:
> But you can't convert a delegate to a function without passing 
> the delegate to
> the function one way or another, because the function doesn't 
> have a context
> (not being a delegate).

That's the whole point of the question - you _can_ pull this off 
if you create a small code fragment somewhere in memory which 
calls the delegate with that specific context argument, and then 
set your function pointer to its address (similar to thunks in 
most vtable implementations or SEH, if you are familiar with 
these). Now, the only problem is that executing data is not quite 
easy, mostly because of security mechanisms (W^X, NX and friends).

As for the original question, I didn't need the feature so far 
(many C libraries provide a void* bit of data to use at the 
client's discretion), but if you need inspiration on how to 
implement it, I'd look at projects like Mono and FFI libraries 
which likely need to provide similar functionality.

Would probably be a good addition to Phobos.

David