[Swift-devel] app semantics

[Mihael Hategan]

Maybe we talked about this before, but I think we should allow things
like:

app (file outf) myapp(file inf) {
	file tmp <"tmpfile">;
	a filename(inf) stdout=filename(tmp);
	b filename(tmp) stdout=filename(outf);
}

In a more general and theoretical sense, an app block can allow some
delimited side-effects while enforcing sequential execution.

>From a practical perspective, this would solve the problem of large
temporary files being staged in and out needlessly (e.g. tmpfile in our
case).

Mihael