Why is the compiler complaining about default argument values?

Re: Why is the compiler complaining about default argument values?

unfortunately you cannot mix overloading and default arguments... (well, you can have _one_ method with
defaults, but not more than one). this was done for simplicity, even if it would be possible to allow both
overloading and multiple default arguments.

http://stackoverflow.com/questions/4652095/why-does-the-scala-compiler-disallow-overloaded-methods-with-default-arguments

best, -sciss-


On 1 Feb 2012, at 01:04, Ken McDonald wrote:

> In a class, the following three method signatures are defined:
> 
> 	def insert(at: Int, insertee: Mark, direction: Direction = Forward): Mark = ...
> 	def insert(at: Mark, insertee: Mark, direction: Direction = Forward): Mark = ...
> 	def insert(at: Mark, content: Content, direction: Direction);
> 
> The types of arguments ensure that there can be no possible ambiguity as to which is called (there is no
inheritance between Content and Mark). However, the compiler says:
> 
>     error: in trait Element, multiple overloaded alternatives of method insert define default arguments.
> trait Element {
> 
> Why is this a problem? There's no erasure happening, so I don't see why there would be any run-time ambiguity.
> 
> Thanks,
> Ken

Advance Actors documentation or tutorials

Hello friends,

i've got a pretty good background with Java concurrency, but i can't
find any advanced tutorials / documentation for Scala Actors.

The best I found is this (it's in the docs site):
http://docs.scala-lang.org/overviews/core/actors.html

I've already read:

Programming in Scala: A Comprehensive Step-by-Step Guide, 2nd Edition
(Odersky, et al)

Programming Scala: Scalability = Functional Programming + Objects
(Payne, et al)

Thank you very much!

--

-- 
Santiago Basulto.-

Is this a known bug?

Re: Advance Actors documentation or tutorials

Hi,

On Feb 1, 2012, at 5:08 AM, Santiago Basulto wrote:

> Hello friends,
> 
> i've got a pretty good background with Java concurrency, but i can't
> find any advanced tutorials / documentation for Scala Actors.

You might want to have a look at the book "Actors in Scala" (Artima, 2011). It contains more advanced
documentation for Scala Actors, as well as material on Akka actors.

Cheers,
Philipp

> 
> The best I found is this (it's in the docs site):
> http://docs.scala-lang.org/overviews/core/actors.html
> 
> I've already read:
> 
> Programming in Scala: A Comprehensive Step-by-Step Guide, 2nd Edition
> (Odersky, et al)
> 
> Programming Scala: Scalability = Functional Programming + Objects
> (Payne, et al)
> 
> Thank you very much!
> 
> -- 
> Santiago Basulto.-

RE: Inferring type of None

Re: Inferring type of None

Re: Inferring type of None

Can we please stop using `asInstanceOf` to "let the type inferencer
work"? That's nowhere near a "solution" to your problem.

If you need a `None` which is of type `Option[X]`, use `Option.empty[X]`.

Re: Inferring type of None

Alternatively: Option.empty[MyType]

On 1 February 2012 08:56, Edmondo Porcu <edmondo.porcu@...> wrote:
> Yes sorry I oversimplified the example.
>
> The solution I found to let the type inferer work is the following:
>
> None.asInstanceOf[Option[MyType]]
>
> Best Regards
>
>
> 2012/2/1 Chris Marshall <oxbow_lakes@...>
>>
>> I think you'll find that Nothing is a subtype of Int
>>
>> > Subject: Re: [scala-user] Inferring type of None
>> > From: contact@...
>> > Date: Tue, 31 Jan 2012 18:19:31 +0000
>> > CC: scala-user@...
>> > To: edmondo.porcu@...
>>
>> >
>> > first of all, B <: Int doesn't make sense. Int is a final type, there
>> > cannot be any subtype of Int
>> >
>>
>

Re: Re: Inferring type of None