Learning delegates

[Bert]

On Sunday, 8 September 2019 at 10:04:57 UTC, Joel wrote:
> I'm trying to understand delegates. Is there any good ways I 
> can get a better understanding of them?

Simple, don't make it harder than it is.

Delegates are basically functions... that is, function 
pointers(they point to some function somewhere in space)... BUT 
they include a "context". The context a scope.


{  // In some scope

    int x;
    d = () { writeln(x); };
}


() { writeln(x); };

is the function defined as a lambda(inline).

It accesses a variable outside of it, that is, in the scope... 
which is called the context.

d is the delegate, it is a function pointer that holds the 
function AND the context pointer.

We can then do

d();

which called/executes the function... the function is called, and 
x can be referenced because d stores the context.

If you do not understand functions, then function pointers, you 
can't understand delegates.