This is a really obvious problem in retrospect, which makes me feel rather
silly.
The output was useful, but I don't have time to deal with this any further
right now. The comments in the commit explain the problem---that the output
ends up being interpolated as part of the fixpoint test, in an incorrect
context, and so the code that we generate is invalid. Also goes to show why
the fixpoint tests are important.
(Yes, they're still disabled for meta-interp, I'm trying to get them
enabled.)
DEV-13163
This introduces the ability to specify an edge ordering for the ontological
tree traversal. `tree_reconstruction` will now use a
`SourceCompatibleTreeEdgeOrder`, which will traverse the graph in an order
that will result in a properly ordered source reconstruction. This is
needed for template headers, because interpolation causes
metavariables (exposed as template params) to be mixed into the body.
There's a lot of information here, including some TODOs on possible
improvements. I used the unstable `is_sorted` to output how many template
were already sorted, based on one of our very large packages internally that
uses templates extensively, and found that none of the desugared shorthand
template expansions were already ordered. If I tweak that a bit, then
nearly all templates will already be ordered, reducing the work that needs
to be done, leaving only template definitions with interpolation to be
concerned about, which is infrequent relative to everything else.
DEV-13163
Well, this is both good news and bad news.
The good news is that this finally produces the expected output and
reconstructs sources from interpolated values on the ASG. Yay!
...the bad news is that it's wrong. Notice how the fixpoint test is
disabled.
So, my plan was originally to commit it like this first and see if I was
comfortable relaxing the convention that `<param>` nodes had to appear in
the header. That's nice to do, that's cleaner to do, but would the
XSLT-based compiler really care? I had to investigate.
Well, turns out that TAMER does care. Because, well over a decade ago, I
re-used `<param>`, which could represent not only a template param, but also
a global param, or a function param.
So, XML->NIR considers all `<param>` nodes at the head of a template to be
template parameters. But after the first non-header element, we transition
to another state that allows it to be pretty much anything.
And so, I can't relax that restriction.
And because of that, I can't just stream the tree to the xmli generator,
I'll have to queue up nodes and order them.
Oh well, I tried.
DEV-13163
Mike Gerwitz