This required rebuilding the matcher compiler significantly, and it
was a lot a lot of work. But now we don't generate so many spurious
newlines and the document we produce is a lot a lot better.
It's weird that it counts against the line length though, like if you
were going to break you could ignore it right? At least, for the
grammar I'm working here....
Now we're cooking with gas ALTHOUGH now we have to deal with the fact
that we're gluing everything together where there *should* be spaces.
Many more improvements to come.
Remember that tree levels are generated by context free languages, not
regular languages, and so they can only be recognized by push-down
automatons, not finite state machines.
What happened was that I failed to account for transparent rules.
Without transparent rules the children of a tree node do not have any
recursion in them (by definition!) and so therefore *are* a regular
language. But transparent rules change that: there *can be* recursion
hidden on the same tree level, and it should have been clear from a
moment's reflection that the recursion there meant that tree levels
were once again a context free language.
Fortunately we have a recognizer for context free languages lying
around, so we can just use that I guess.
Still very garbage but I think the "hard" part of building a Wadler
document from a parse tree might be there. It's a backtracking matcher
which might turn out to be too slow for alternatives but maybe will be
fine?
Still needs lots of tests.
