I had intended for this to be a full vertical slice initially, but AIR's
parser is going to need enough work that it'll muddy this patch a bit too
much.
This keeps the desugaring simple, which is what I was hoping for.
The next step is to load it into the graph and emit regenerated longhand
sources.
I also don't like how the namespace prefix is just being ignored for
shorthand param desugaring. This is also the case in the XSLT-based
compiler, but this violates TAMER's principle that it should parse every bit
of information; nothing should be ignored. If something does not contribute
useful information, then it is not a useful construct and ought to be
rejected.
DEV-13708
This moves translation from NirToAir into TplShortDesugar, and changes the
output from AIR to NIR.
This is going to be much easier to reason about as a desugaring
operation (and indeed that's always how TAME has implemented it, in XSLT);
this keeps the complexity isolated.
Ideally, NirToAir wouldn't even accept tokens that it can't handle, but
that's going to take quite a bit more work and I don't have the time right
now. Instead, we'll fail at runtime with some hopefully-useful
information. It shouldn't actually happen in practice.
DEV-13708
Mike Gerwitz