The importance of API design

Reflecting on the exercise leading up to yesterday's post, one of the things that struck me in the comparison of the .net Framework used from F# and the Java APIs available to Scala/JVM was how much the former got little details right to facilitate working in the web-page embedded context. Take the simple task of getting at the URL query parameters for the page in which the applet is embedded

In Silverlight, in the main UserControl class:

In an applet, where peer is the Applet instance:

Perhaps this just shows how the old-style Java applet has withered on the vine, while Silverlight as a competitor to Flash has taken on a more aggressive stance for developer acceptance -- but with the decade-plus that Java has under its belt compared with Silverlight's barely more than a year (1.0 not really counting), the comparison is rather disappointing.

I shall have to investigate whether the continued work on scala-msil has led to any material improvements in its robustness since I looked at it last, six months ago.

A few minutes later

Well, my six month old port of the Scala actors package to pure Scala calling the .Net APIs still blows the compiler up in a Scala 2.8 nightly that's just a few days old. The explosion is in pure Scala code taken directly from the 2.7.5 actors package, and not the Scala-calling-.net replacements I coded of the Java parts of that package:

object Eval$2
  symbol = final case  object Eval$2
  owner  = final  object Futures
with methods = List(scala.actors.Futures.Eval$2., scala.actors.Futures.Eva
l$2.readResolve, scala.actors.Futures.Eval$2.canEqual, scala.actors.Futures.Eval
$2.productElement, scala.actors.Futures.Eval$2.productArity, scala.actors.Future
s.Eval$2.productPrefix, scala.actors.Futures.Eval$2.toString, scala.actors.Futur
es.Eval$2.productElements, scala.actors.Futures.Eval$2.productIterator)
Exception in thread "main" java.lang.RuntimeException: ILGenerator.emit(): Stack
 underflow in method: public static System.Void scala.actors.Futures$+scala.acto
rs.Futures.Eval$2$::.cctor()
        at ch.epfl.lamp.compiler.msil.emit.ILGenerator.emit(ILGenerator.scala:48
7)

So, still not ready for prime-time.