Please pardon me if this is the wrong place to raise this issue for
consideration. On other projects, I have been turned back on
StackOverflow for attempting to discuss unreleased software.

At some point down the road, I believe that users of sbt-cross will
encounter a 2-out-of-3, more generally, m-out-of-N, problem
handling source directories, settings, etc. Examples of
solutions which do not fall into combinatorial complexity
will be useful to those users.

To get the existing sbt-cross trio project working with a
main program (1), I had to create a HelloWorld.scala
in each of bar/js/src, bar/jvm/src, and bar/native/src.
The js/src/HelloWorld.scala had to be different (until
I can figure out a better way). The bar/jvm and bar/native
files were identical, which violates DRY. To keep some
sanity, I do want to use symlinks.

Flush from success at getting the sbt-cross trio example
project working (Thank you for the example!), I tried to add
test tree code. Since it is, understandably, too soon for
scala-native to support uTest, I wanted to be prepared
and get up to speed by testing scalaJS vs scalaJVM.
Is there a better place for discussion?

This left me with a situation where I needed to enter
settings common to the scalaJS & scalaJVM sub-projects,
but not the scala-native project. Someday I may
be clever enough to figure out some elegant sbt/scala
code to do this, but for now I duplicated (and the
spirits of my mentors yelled at me, for good reason).

When I set up the testing directories, I ran into
a similar problem. I had to duplicate
the tree in js/src/test to jvm/src/test. Surely
a cause for future, self-inflicted pain.

I can also foresee situations where one would want
scalaJVM & scala-native in the mix and scalaJS out.

With time, I hope to figure out some clever way of
handling these 2-out-of-3 issues without falling into
combinatorial complexity. The sbt settings issue
is probably simpler than the duplicated tree issue.

I mention instances of this issue early on for "back of the brain'
consideration because I think other developers will
run straight into them as the try to stretch from the
well explored & experienced scalaJS/scalaJVM duo
to the nova mundi of scalaJS/scalaJVM/scala-native trio.

Thank you for any suggestions, including
"Please be patient until sbt-cross matures".

Lee

1. At this point, the sbt-native HelloWorld.scala is
   scaffolding and/or a thought experiment. sbt-native
   seems to have a problem and generate null output to stdout.
   In the fullness of time that will get fixed.