See the Air docblock for more information. I'm introducing new tokens for
the template system, which uses the terms "free" and "closed". I prefer
open/close for delimiters, as I've expressed elsewhere, but unfortunately it
conflicts too much (and too confusingly) with other standard terminology as
we get more into the formal side of the language.
DEV-13708
The intent was to have a very simple implementation of `hold_dangling` and
have everything work. But, I had a nasty surprise when the system tests
caught bug caused by some interesting depth interactions as it relates to
`xmli` and auto-closing.
I added an extra test/example in `asg::graph::visit::test` to illustrate the
situation; it was difficult to derive from the traces, but trivially obvious
once I wrote it out as an example.
With that, templates can now aggregate tokens for dangling expressions.
DEV-13708
This hoists the errors back into `AirAggregate`; I need dead states for the
`AirTplAggregate` parser so that it will know when to (and not to) interpret
tokens in the context of the template itself.
In a previous commit message, I had pondered whether it may be possible to
eliminate the dead state transition, and yet here I've used it with both of
the sub-parsers now. So it seems like the better option in the future may
be to narrow the type further---to say precisely _what_ types of tokens may
yield a dead state transition; otherwise you lose the match information from
the parser that yielded it.
A stubbornly persistent problem in Rust, this magical and hidden match
knowledge.
DEV-13708
This sets us up to be able to determine how `Dangling` expressions will be
rooted into templates.
This new strategy isn't yet handling `Dangling`; I wanted to get this
committed first so that the `Dangling` refactoring is more clear.
DEV-13708
Expressions were previously tied to packages. This prepares for using a
`Tpl` as a container for expressions.
This does not yet handle the situation of auto-rooting dangling expressions
within the container.
DEV-13708
This result in less useful debug output, but it'll be needed for using
a (possibly-anonymous) template as evidence.
This evidence is simply for debugging, and to require some sort of value
during development to help obviate when maybe something is being done
incorrectly (if no obvious value exists).
DEV-13708
This is more of the same refactoring that has been happening. This
extraction also helps emphasize the relationship between imported objects,
and isolates the growing number of test cases. This parser will only grow.
DEV-13708
Mike Gerwitz