Mike Gerwitz
61f7a12975
Note that AttrParse{r=>}State needs renaming, and Stack will get a better
name down the line too. This commit message is accurate, but confusing.
This performs the long-awaited task of trying to observe, concretely, how to
combine two automata. This has the effect of stitching together the state
machines, such that the union of the two is equivalent to the original
monolith.
The next step will be to abstract this away.
There are some important things to note here. First, this introduces a new
"dead" state concept, where here a dead state is defined as an _accepting_
state that has no state transitions for the given input token. This is more
strict than a dead state as defined in, for example, the Dragon Book, where
backtracking may occur.
The reason I chose for a Dead state to be accepting is simple: it represents
a lookahead situation. It says, "I don't know what this token is, but I've
done my job, so it may be useful in a parent context". The "I've done my
job" part is only applicable in an accepting state.
If the parser is _not_ in an accepting state, then an unknown token is
simply an error; we should _not_ try to backtrack or anything of the sort,
because we want only a single token of lookahead.
The reason this was done is because it's otherwise difficult to compose the
two parsers without requiring that AttrEnd exist in every XIR stream; this
has always been an awkward delimiter that was introduced to make the parser
LL(0), but I tried to compromise by saying that it was optional. Of course,
I knew that decision caused awkward inconsistencies, I had just hoped that
those inconsistencies wouldn't manifest in practical issues.
Well, now it did, and the benefits of AttrEnd that we had in the previous
construction do not exist in this one. Consequently, it makes more sense to
simply go from LL(0) to LL(1), which makes AttrEnd unnecessary, and a future
commit will remove it entirely.
All of this information will be documented, but I want to get further in
the implementation first to make sure I don't change course again and
therefore waste my time on docs.
DEV-11268
|
||
|---|---|---|
| .. | ||
| benches | ||
| build-aux | ||
| src | ||
| .gitignore | ||
| Cargo.lock | ||
| Cargo.toml | ||
| Makefile.am | ||
| README.md | ||
| autogen.sh | ||
| bootstrap | ||
| configure.ac | ||
| rustfmt.toml | ||
README.md
TAME in Rust (TAMER)
TAME was written to help tame the complexity of developing comparative insurance rating systems. This project aims to tame the complexity and performance issues of TAME itself. TAMER is therefore more tame than TAME.
TAME was originally written in XSLT. For more information about the
project, see the parent README.md.
Building
To bootstrap from the source repository, run ./bootstrap.
To configure the build for your system, run ./configure. To build, run
make. To run tests, run make check.
You may also invoke cargo directly, which make will do for you using
options provided to configure.
Note that the default development build results in terrible runtime performance! See [#Build Flags][] below for instructions on how to generate a release binary.
Build Flags
The environment variable CARGO_BUILD_FLAGS can be used to provide
additional arguments to cargo build when invoked via make. This can be
provided optionally during configure and can be overridden when invoking
make. For example:
# release build
$ ./configure && make CARGO_BUILD_FLAGS=--release
$ ./configure CARGO_BUILD_FLAGS=--release && make
# dev build
$ ./configure && make
$ ./configure CARGO_BUILD_FLAGS=--release && make CARGO_BUILD_FLAGS=
Hacking
This section contains advice for those developing TAMER.
Running Tests
Developers should be using test-driven development (TDD). make check will
run all necessary tests.
Code Format
Rust provides rustfmt that can automatically format code for you. This
project mandates its use and therefore eliminates personal preference in
code style (for better or worse).
Formatting checks are run during make check and, on failure, will output
the diff that would be applied if you ran make fmt (or make fix); this
will run cargo fmt for you (and will use the binaries configured via
configure).
Since developers should be doing test-driven development (TDD) and therefore
should be running make check frequently, the hope is that frequent
feedback on formatting issues will allow developers to quickly adjust their
habits to avoid triggering formatting errors at all.
If you want to automatically fix formatting errors and then run tests:
$ make fmt check
Benchmarking
Benchmarks serve two purposes: external integration tests (which are subject
to module visibility constraints) and actual benchmarking. To run
benchmarks, invoke make bench.
Note that link-time optimizations (LTO) are performed on the binary for benchmarking so that its performance reflects release builds that will be used in production.
The configure script will automatically detect whether the test feature
is unstable (as it was as of the time of writing) and, if so, will
automatically fall back to invoking nightly (by running cargo +nightly bench).
If you do not have nightly, run you install it via rustup install nightly.