When I execute (bash command line) a simple hello_world.scala program (see below)
which uses the 2..0 "object extends App" idiom using two steps scalac hello_world.scala,
then scala hello_world, the program prints out the greeting as expected.

When I do a simple "scala hello_world.scala", the program appears to compile, then
return to the command line without having printed anything. The documentation I read
(2.9.0, various RC variants) seemed to indicate that the two ways of executing should
be the same. When I use the older idiom of an explicit main(), I get the same printout
both ways.

I appears that the delayedInit is never being called in the "scala object extends App" case.

Pardon me if this "feature" is documented and I missed it, or if I have a total misunderstanding
of intended behavior. BTW, I've written in a number of languages and Scala is great; explicit but
lightweight. Thank you all for creating & growing it.

object HwApp extends App {
printf("\nHello world App\n")
}

I can work around this in a Makefile, but it seems like either it should work or
I should learn more scala to understand why it does not.