Variable number of parameters

[Vitaly Davidovich]

This probably comes down to cost/benefit - it would seem that the
complication in inference and disambiguation isn't worth the cost for such
a minor convenience.

C#, for example, does not support this type of thing either (they do
support the case where you don't use any of the parameters though).

Just my 2 pennies though ...
On Dec 5, 2011 6:23 PM, "Stephen Colebourne" <scolebourne at joda.org> wrote:

> Consider this looping method (on a DoubleList class for simplicity of
> discussion):
>
> interface IndexedBlock {
>  void apply(Double value, int index);
> }
> class DoubleList {
>  public void each(IndexedBlock block);
> }
>
> To fulfil this functional interface, the writer of the lambda must
> specify two parameters:
>
>  list.each( (value, index) -> print("Index " + index + " value " + value)
> );
>
> But, it would be convenient to be able to only specify the index if
> required when writing the lambda:
>
>  list.each( value -> print("Value " + value) );  // this still uses
> IndexedBlock!
>
> The example here is based on Fantom, but probably occurs in other
> languages. It is important, because it affects the way in which the
> APIs are designed - access to the index while looping can be provided
> with an additional parameter that is only used when necessary, rather
> than needing to provide a separate "eachIndexed()" method.
>
> Of course, such an approach complicates inference, and adds
> complexity, taking lambdas further away from inner classes. Its
> possible that the EDR allows this, but I don't think it does.
>
> I raise it as I don't recall a discussion here about this (not because
> I necessarily think its right for Java).
>
> Stephen
>
>