match issue

[Konstantine Kougios]

Hi,

    I came up to this weird thingy:

scala> val f =(x:Any,y:Any)=> x match {                                          
     | case _: Int | Boolean | Long | Float | Double | Byte | Short | Char => x==y
     | }
f: (Any, Any) => Boolean = <function2>

scala> f(5d,5d)
scala.MatchError: 5.0
    at $anonfun$1.apply(<console>:5)
    at $anonfun$1.apply(<console>:5)
    at .<init>(<console>:7)
    at .<clinit>(<console>)
    at RequestResult$.<init>(<console>:9)
    at RequestResult$.<clinit>(<console>)
    at RequestResult$scala_repl_result(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$17.apply(Interpreter.scala:988)
    at scala.tools.nsc.Interpreter$Request$$anonfun$loadAndRun$1$$anonfun$apply$17.apply(Interpreter.scala:988)
    at scala.util.control.Ex...



Why doesn't it match the double value?

Cheers

[Roland Kuhn]

Hi Konstantine,

you might have been tricked into thinking that you included the type Double in the pattern match, but you actually have only object Double there. Each one of the | separated sub-patterns must be complete by itself, i.e. include _: in your case.

Regards,

Roland

Roland Kuhn

Typesafe – Enterprise-Grade Scala from the Experts

twitter: @rolandkuhn

[Konstantine Kougios]

Ok, I see, thanks