class constructors in Xtend

Question

I'm trying out Xtend. Is it possible to make constructors? It seems so simple, but I'm getting an error when I try something like this:

class Scope extends Rect {

    public Scope(){
        super()
    }

}

Ahaa! That works. Now how would I access the superclass constructor? `super` doesn't seem to work as it usually does. Still new to this. — brendanzab, Nov 07 '11 at 10:18
Just a followup, see the comment below for an explanation. It didn't actually work. ;) — brendanzab, Nov 08 '11 at 22:21

score 13 · Accepted Answer · edited Oct 17 '19 at 07:58

13

Constructors are defined by overloading a new() method:

class MyClass extends AnotherClass {
  new(String s) {
    super(s)
  }

  new() {
    this("default")
  }
}

look here

edited Oct 17 '19 at 07:58

Community

1
1

answered Feb 07 '12 at 12:51

Lev

921
7
15

score 2 · Answer 2 · answered Nov 14 '11 at 07:44

2

The next release of Xtend is planned for mid December. It'll have support for declaring constructors.

See http://www.eclipse.org/Xtext/xtend/#whatsnext

answered Nov 14 '11 at 07:44

Sven Efftinge

3,065
17
17

score 1 · Answer 3 · answered Nov 08 '11 at 19:29

1

Constructors are not yet supported in Xtend. The suggestion def Scope() is more a bug than a working constructor. You may want to follow this ticket.

answered Nov 08 '11 at 19:29

Sebastian Zarnekow

6,609
20
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score 1 · Answer 4 · answered Nov 08 '11 at 20:42

1

There is no constructor support in Xtend 2.0. I think it is a show stopper.

"class Foo { def Foo() { /stuff/ } } declares a method Foo on instances of Foo with the inferred return type, not a constructor, as browsing the generated Java code will show.

This implies that there is no way to extend Java classes that lack default constructors. XTend does not complain; it happily generates Java that does not compile.

Nor does XTend support immutable (final) instance variables, naturally enough.

answered Nov 08 '11 at 20:42

Dzhaughn

114
1
4

Cheers dude. Definitely a show stopper. This has actually made me look at into scala. – brendanzab Nov 08 '11 at 22:20
1

This has changed in Xtend 2.1; there are other substantial improvements as well. Still no final variables. – Dzhaughn Jan 13 '12 at 08:17

class constructors in Xtend

4 Answers4