Parameters List (*) in Scala

On Thu, Jan 12, 2012 at 06:07:21PM +0100, Edmondo Porcu wrote:
> error: type mismatch;
> found : Range*
> required: Range

Hi Edmondo,

I thin you want to use :_*

For instance:

def foo(ns:Int*) = ns.sum
def bar(ns:Int*) = foo(ns:_*) * 2

Hope this helps!

varargs (the last parameter with an asterisk) allow you to _call_ that method with variable arguments, but inside the method body they appear collected into a sequence under the name of the argument (otherwise how would you distinguish them?). so you are trying to call a method skipSomething( _: Int, _: Seq[Range]). you can expand a sequence to varargs again for a subsequent call through the special type _* :

def filterYears(toSkip: Range*) = skipSomething(12,toSkip: _*)

best, -sciss-

On 12 Jan 2012, at 17:07, Edmondo Porcu wrote:

> Dear all,
> I have a problem with parameters list in Scala.... I obtain a type mismatch which I am not expecting:
>
> def filterYears(toSkip: Range*) = skipSomething(12,toSkip);
>
> def filterMonths(toSkip: Range*) = skipSomething(1,toSkip)
>
>
> private def skipSomething( multiplier:Int,toSkip:Range*){}
>
> Results in the following compiler error:
>
> error: type mismatch;
> found : Range*
> required: Range
> def filterYears(toSkip: Range*) = skipSomething(12,toSkip);
>
>
> error: type mismatch;
> found : Range*
> required: Range
> def filterMonths(toSkip: Range*) = skipSomething(1,toSkip)
>
> What is the reason for that?
>
> Best Regards

Am 12.01.2012 18:11, schrieb Sciss:
> varargs (the last parameter with an asterisk) allow you to _call_ that method with variable arguments, but inside the method body they appear collected into a sequence under the name of the argument (otherwise how would you distinguish them?). so you are trying to call a method skipSomething( _: Int, _: Seq[Range]). you can expand a sequence to varargs again for a subsequent call through the special type _* :
>
> def filterYears(toSkip: Range*) = skipSomething(12,toSkip: _*)
and that one goes into the cheat sheet, too

>
> best, -sciss-
>
> On 12 Jan 2012, at 17:07, Edmondo Porcu wrote:
>
>> Dear all,
>> I have a problem with parameters list in Scala.... I obtain a type mismatch which I am not expecting:
>>
>> def filterYears(toSkip: Range*) = skipSomething(12,toSkip);
>>
>> def filterMonths(toSkip: Range*) = skipSomething(1,toSkip)
>>
>>
>> private def skipSomething( multiplier:Int,toSkip:Range*){}
>>
>> Results in the following compiler error:
>>
>> error: type mismatch;
>> found : Range*
>> required: Range
>> def filterYears(toSkip: Range*) = skipSomething(12,toSkip);
>>
>>
>> error: type mismatch;
>> found : Range*
>> required: Range
>> def filterMonths(toSkip: Range*) = skipSomething(1,toSkip)
>>
>> What is the reason for that?
>>
>> Best Regards
>