Some investigation into the disassembly of TAMER's binaries showed that Rust
was not able to conditionalize `expect`-like expressions as I was hoping due
to eager evaluation language semantics in combination with the use of
`format!`.
This solves the problem for the diagnostic system be creating types that
prevent this situation from occurring statically, without the need for a
lint.
This extracts error tracking into the Reporter itself, which is already
shared between lowering operations. This can then be used to display the
number of errors.
A new formatter (in tamer::fmt) will be added to handle the singular/plural
conversion in place of "error(s)" in the future; I have more important
things to work on right now.
DEV-13158
This change introduces diagnostic messages for panics. The intent is to be
able to use panics in situations where it is either not possible to or not
worth the time to recover from errors and ensure a consistent/sensible
system state. In those situations, we still ought to be able to provide the
user with useful information to attempt to get unstuck, since the error is
surely in response to some particular input, and maybe that input can be
tweaked to work around the problem.
Ideally, invalid states are avoided using the type system and statically
verified at compile-time. But this is not always possible, or in some cases
may be way more effort or cause way more code complexity than is worth,
given the unliklihood of the error occurring.
With that said, it's been interesting, over the past >10y that TAME has
existed, seeing how unlikely errors do sometimes pop up many years after
they were written. It's also interesting to have my intuition of what is
"unlikely" challenged, but hopefully it holds generally.
DEV-7145
Values can be parsed using `TryFrom<Attr>`. Previously only `From<Attr>`
was supported, which could not fail.
This is critical for parsing values into types, which will wrap `SymbolId`
to provide data assurances.
DEV-7145
This is the first parser generator for the parsing framework. I've been
waiting quite a while to do this because I wanted to be sure that I
understood how I intended to write the attribute parsers manually. Now that
I'm about to start parsing source XML files, it is necessary to have a
parser generator.
Typically one thinks of a parser generator as a separate program that
generates code for some language, but that is not always the case---that
represents a lack of expressiveness in the language itself (e.g. C). Here,
I simply use Rust's macro system, which should be a concept familiar to
someone coming from a language like Lisp.
This also resolves where I stand on parser combinators with respect to this
abstraction: they both accomplish the exact same thing (composition of
smaller parsers), but this abstraction doesn't do so in the typical
functional way. But the end result is the same.
The parser generated by this abstraction will be optimized an inlined in the
same manner as the hand-written parsers. Since they'll be tightly coupled
with an element parser (which too will have a parser generator), I expect
that most attribute parsers will simply be inlined; they exist as separate
parsers conceptually, for the same reason that you'd use parser combinators.
It's worth mentioning that this awkward reliance on dead state for a
lookahead token to determine when aggregation is complete rubs me the wrong
way, but resolving it would involve reintroducing the XIR AttrEnd that I had
previously removed. I'll keep fighting with myself on this, but I want to
get a bit further before I determine if it's worth the tradeoff of
reintroducing (more complex IR but simplified parsing).
DEV-7145
This is intended to describe, to the user, the state that the parser is
in. This will be used to convey additional information for general parser
errors, but it should also probably be integrated into parsers' individual
errors as well when appropriate.
This is something I expected to add at some point, but I wanted to add them
because, when dealing with lowering errors, it can be difficult to tell
what parser the error originated from.
DEV-11864
RSG (Ryan Specialty Group) recently announced a rename to Ryan Specialty (no
"Group"), but I'm not sure if the legal name has been changed yet or not, so
I'll wait on that.
I had waited to provide more documentation until I was sure that the
abstraction was not going to change significantly; there was a lot of
refactoring in prior commits.
DEV-12151
`SpanLabel` was created during a very early refactoring of this system, and
I've just been fighting with it sense. This removes it, and simplifies
some things in the process.
It also makes clear that `Level` is never optional and removes the awkward
`Level::default` that was there previously; the default is now the lowest
level, which will always be able to be escalated.
DEV-12151
I'm unhappy with the current state of this, which is why I haven't settled
on docs or unit tests for these changes yet (though note that the
integration tests do cover these changes)---this is still a prototype
refactoring.
In particular, this needs to do more lowering---the `ResolvedSpan` and
`MaybeResolvedSpan` need to be eliminated and lowered into exactly what is
needed so that we can stop reasoning about them and propagating them.
Further, having lines and columns lazily evaluate themselves for
display---based on `MaybeResolvedSpan`---adds extra generics that shouldn't
be necessary; they should be pre-computed and store the concrete data they
need in variants. Display shouldn't involve computation beyond formatting
of pre-computed data.
That was always the plan, but this refactoring has been incremental.
Anyway: this is in a working and integration-tested state, but it's going to
change.
DEV-12151
I did not initially introduce lifetimes because I wasn't sure how the system
was going to evolve, but now lifetimes are going to be needed in a number of
contexts. The core of TAMER is able to avoid lifetimes in most instances
because of its internment system, but its use is not appropriate for the
diagnostic system's buffers (beyond sourcing strings from already-interned
data).
DEV-12151
This works, but it's ugly and requires some cleanup. It shows that there
are some interesting considerations when determining how to best represent
the location of spans to the user in a way that is intuitive.
This is not yet integrated with the reporter, which will require a layer to
load a `Context` from disk.
DEV-10935
This is a working concept that will continue to evolve. I wanted to start
with some basic output before getting too carried away, since there's a lot
of potential here.
This is heavily influenced by Rust's helpful diagnostic messages, but will
take some time to realize a lot of the things that Rust does. The next step
will be to resolve line and column numbers, and then possibly include
snippets and underline spans, placing the labels alongside them. I need to
balance this work with everything else I have going on.
This is a large commit, but it converts the existing Error Display impls
into Diagnostic. This separation is a bit verbose, so I'll see how this
ends up evolving.
Diagnostics are tied to Error at the moment, but I imagine in the future
that any object would be able to describe itself, error or not, which would
be useful in the future both for the Summary Page and for query
functionality, to help developers understand the systems they are writing
using TAME.
Output is integrated into tameld only in this commit; I'll add tamec
next. Examples of what this outputs are available in the test cases in this
commit.
DEV-10935
Mike Gerwitz