trouble building mlvm

[Iulian Dragos]

Good to see your neck is better!

On Wed, Dec 17, 2008 at 12:21 AM, Paul Phillips <paulp at improving.org> wrote:
> You are quite right, the whole java.dyn package wasn't being built.  I will guess that when the mlvm
> patches were last tested, the make system built whatever files it found - but now it only builds what is
> specifically enumerated.  I mimicked another java package to get it built, as shown in this patch:
>
>  http://www.improving.org/scala/openjdk.diff

Thanks for the patch. So far, I built those files the old fashioned
way (javac `find jdk/src/... -iname *.java`), and it seems I'm finally
getting somewhere! I had to remove the 'MethodHandles' XX flag (my vm
does not recognize it), but then I got one step further:


> [paulp at jon demo (exp)]$ scala
> Welcome to Scala version 2.7.2.final (OpenJDK Server VM, Java 1.7.0-internal).
> Type in expressions to have them evaluated.
> Type :help for more information.
>
> scala> import java.dyn._
> import java.dyn._
>
> scala> class Foo { def bar(s: String): Unit = { } }
> defined class Foo
>
> scala> val fooType = MethodType.make(classOf[Unit], Array[Class[_]](classOf[String]), false)
> fooType: java.dyn.MethodType = (java.lang.String)void
>
> scala> val fooHandle = MethodHandles.findVirtual(classOf[Foo], "bar", fooType)
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> #  SIGBUS (0xa) at pc=0x01366b0f, pid=49241, tid=2953121792
> #
> # Java VM: OpenJDK Server VM (14.0-b08 mixed mode bsd-x86 )
> # Problematic frame:
> # V  [libjvm.dylib+0x366b0f]
> #

scala> val fooHandle = MethodHandles.findVirtual(classOf[Foo], "bar",
fooType)
fooHandle: java.dyn.MethodHandle = bar:(Foo,java.lang.String)void

scala> fooHandle.invoke(new Foo, "abc")
<console>:10: error: value invoke is not a member of java.dyn.MethodHandle
       fooHandle.invoke(new Foo, "abc")
                 ^

Hurray!

The error is due to the Scala type checker not knowing that
MethodHandles are special. I'll have to try John's example in the
morning, I had enough excitement for one evening :)

> Let us keep soldiering onward, I can see the train at the end of the tunnel...

And its lights are on!

Cheers,
Iulian

-- 
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Alphonse Allais