Hi Blackdrag
On 7. mar. 2016, at 10.02, Jochen Theodorou <[email protected]> wrote:
>
> On 07.03.2016 07:48, Jesper Steen Møller wrote:
> [...]
>>
>> So you can help me with a couple of answers:
>>
>> * Is it a goal to close the gap to Java’s more trickier syntax, such
>> as placement-new and placement constructor calls? From what I can
>> tell, we’d have to extend the AST too to support that. Has anyone
>> ever used that except in compiler test cases?
>
> I had to actually look up what you mean... so you can give type arguments in
> a constructor call? I did actually not know this. I would not give this one
> any priority, unless it is easy to do… but then I would not really give it an
> AST implementation yet
It’s certainly not something which is used a lot. Yes, you can declare type
parameters for constructors like you can for methods. This is not supported in
Groovy for now - neither is calling one.
Actually, placement new and placement constructor calls are different from
explicit type arguments.
Placement new is used to specify the ‘outer’-instance for inner classes, and .
I really dont think anyone does that in practise - here is an example:
public class A {
A(String name) {
this.me = name;
}
String me;
public class B {
String who() {
return "I'm a B inside " + me;
}
}
public static class C extends B {
C(A outer) {
outer.super(); // This is “placement constructor”,
could be fudged in the AST as function call until late in compilation
}
String who() {
return "I'm a C inheiriting from this guy: " +
super.who();
}
}
public static void main(String[] args) {
A a1 = new A("John");
A a2 = new A("Paul");
B b = a1.new B(); // This is "placement new" - may require AST
for groovy, certainly grammar
System.out.println(b.who());
C c = new C(a2);
System.out.println(c.who());
}
}
Just what you always needed, right? I only learned about it from working on the
JDT compiler.
Also - I’m also -1 on introducing these pretty much useless Java features —
it’s not “gratuitous incompatibility”, but major complications without any use.
I’ll keep a list, but stop asking…
>
>> * ./benchmark/bench/heapsort.groovy uses access modfiers on the
>> script’s local variables — that’s not really allowed, is it? How
>> should that work? It can’t get it to work in Groovy 2.4.x
>
> You mean like "public static final long IM = 139968"? It does not really make
> a semantic sense to allow this. For convenient copy&paste this could be
> allowed... if it poses no problem, I think it would be nice to have. But it
> is not really required
>
But what should it mean? Should it become fields in the Script class, or just
be stripped of access and staticness and introduced as locals in the main() ?
Since it doesn’t work in Groovy now, I don’t understand why it’s in the repo at
all…
-Jesper
