Sergey Gromov wrote:
Tue, 04 Aug 2009 11:58:27 -0300, Ary Borenszweig wrote:
Sergey Gromov wrote:
Tue, 04 Aug 2009 22:46:22 +1000, Daniel Keep wrote:
Sergey Gromov wrote:
Tue, 04 Aug 2009 17:22:50 +1000, Daniel Keep wrote:
Don wrote:
...
A question: in C#/Java, can you have annotations on function pointer and
delegate declarations?
void foo( int delegate(int) pure dg) {
...
}
What would this look like with annotations?
Well, Java doesn't HAVE delegates and C# doesn't (AFAIK) allow you to
define them inline; they have a special declaration syntax that can't be
used in an expression.
C#:
List<int> ls;
ls.Sort((x, y) => y - x);
or
ls.Sort((x, y) => { int a; a = y; a -= x; return a; });
That's not a delegate type, that's a delegate literal.
Sorry, you said: "C# doesn't ... allow you to define them (delegates)
inline". Delegate literal *is* an inline definition of a delegate.
What you say now is that C# doesn't allow to define a delegate type
inside a function which is definitely true and is very annoying.
Have you seen the Func delegates? They are exactly for that.
The above example would be:
void foo(Func<int, int> dg) { ... }
Func defines a delegate with one argument and a non-void return. There
are lots of others like Action, Predicate, Comparator etc. which you
must either remember or look up every time you need a specific delegate
signature.
Ah, I didn't know you can't do something like Func<void, int>. So there
could just be two things to remember: Func and Action.
Also you have Func<T1, T2, TResult>, Func<T1, T2, T3, TResult>, so it's
not just one argument.
I just tried casting one delegate type to another one with the same
signature and it doesn't work. So you are right, you need to remember
Predicate, Comparator, etc. :-(
