Since it's generated code anyway, it doesn't need to be formatted
nicely, and rustfmt was spewing out a bunch of errors because of
too-long lines anyway.
The code here is a bit messy right now. Just did enough to get
it working. But it needs to be cleaned up and report parse
errors in a human-readable way, among other things.
It was using bounds-checked indexing in the basic operations. Now
it's using non-bounds-checked indexing, since all of the indexing
is constants that we know to be within the bounds.
