Feature Request: Lambda syntax for single-method interfaces with multiple parameters

Elements Oxygene
1

I would love to be able to use the lambda syntax for single-method interfaces in which the method has multiple parameters. The compiler currently fails when I try this, which I assume is by design based on the documentation:

An alternative syntax for defining anonymous methods is a Lambda expression, which is shorter but cannot provide parameter types and relies on type inference.

For example, the Android API defines interface View.OnClickListener which has a single method onClick (v: View).

Instead of

button.setOnClickListener(new class View.OnClickListener(
  onClick := method(v: View) begin
    { code }
  end
);

I can type

button.setOnClickListener(-> begin
    { code }
end);

and the compiler also allows

button.setOnClickListener((v: View) -> begin
    { code }
end);

where I can reference parameter v from within the method.

But in the different case of the Android API’s DialogInterface.OnClickListener, which defines a single method onClick(v: View; which: Integer), I am forced to use the longer syntax instead of

button.setOnClickListener((v: View; which: Integer) -> begin
    { code }
end);

It would be a great feature to be able to use the lambda syntax in these cases as well, as I’ve run across several single-method, multi-parameter interfaces in the Android API.

2

Doesn’t (v,c) -> begin … End work?

3

Apparently so :slight_smile: I’ve just not seen that in the documentation anywhere.

Thanks!

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