tame/tamer
Mike Gerwitz bfe46be5bb tamer: xir::tree::attr_parser_from: Integrate AttrParser
This begins to integrate the isolated AttrParser.  The next step will be
integrating it into the larger XIRT parser.

There's been considerable delay in getting this committed, because I went
through quite the struggle with myself trying to determine what balance I
want to strike between Rust's type system; convenience with parser
combinators; iterators; and various other abstractions.  I ended up being
confounded by trying to maintain the current XmloReader abstraction, which
is fundamentally incompatible with the way the new parsing system
works (streaming iterators that do not collect or perform heap
allocations).

There'll be more information on this to come, but there are certain things
that will be changing.

There are a couple problems highlighted by this commit (not in code, but
conceptually):

  1. Introducing Option here for the TokenParserState doesn't feel right, in
     the sense that the abstraction is inappropriate.  We should perhaps
     introduce a new variant Parsed::Done or something to indicate intent,
     rather than leaving the reader to have to read about what None actually
     means.
  2. This turns Parsed into more of a statement influencing control
     flow/logic, and so should be encapsulated, with an external equivalent
     of Parsed that omits variants that ought to remain encapsulated.
  3. TokenStreamState is true, but these really are the actual parsers;
     TokenStreamParser is more of a coordinator, and helps to abstract away
     some of the common logic so lower-level parsers do not have to worry
     about it.  But calling it TokenStreamState is both a bit
     confusing and is an understatement---it _does_ hold the state, but it
     also holds the current parsing stack in its variants.

Another thing that is not yet entirely clear is whether this AttrParser
ought to care about detection of duplicate attributes, or if that should be
done in a separate parser, perhaps even at the XIR level.  The same can be
said for checking for balanced tags.  By pushing it to TokenStream in XIR,
we would get a guaranteed check regardless of what parsers are used, which
is attractive because it reduces the (almost certain-to-otherwise-occur)
risk that individual parsers will not sufficiently check for semantically
valid XML.  But it does _potentially_ match error recovery more
complicated.  But at the same time, perhaps more specific parsers ought not
care about recovery at that level.

Anyway, point being, more to come, but I am disappointed how much time I'm
spending considering parsing, given that there are so many things I need to
move onto.  I just want this done right and in a way that feels like it's
working well with Rust while it's all in working memory, otherwise it's
going to be a significant effort to get back into.

DEV-11268
2021-12-10 14:25:08 -05:00
..
benches tamer: xir: Remove Text enum 2021-11-15 23:47:14 -05:00
build-aux Copyright year update 2021 2021-07-22 15:00:15 -04:00
src tamer: xir::tree::attr_parser_from: Integrate AttrParser 2021-12-10 14:25:08 -05:00
.gitignore TAMER: Initial commit 2019-11-18 14:05:47 -05:00
Cargo.lock tamer: Remove tests invoking cargo and associated libs 2021-12-02 12:38:06 -05:00
Cargo.toml tamer: Remove tests invoking cargo and associated libs 2021-12-02 12:38:06 -05:00
Makefile.am tamer: cargo --frozen --offline 2021-12-02 11:49:51 -05:00
README.md Copyright year update 2021 2021-07-22 15:00:15 -04:00
autogen.sh Copyright year update 2021 2021-07-22 15:00:15 -04:00
bootstrap tamer: cargo --frozen --offline 2021-12-02 11:49:51 -05:00
configure.ac tamer: cargo --frozen --offline 2021-12-02 11:49:51 -05:00
rustfmt.toml tamer/rustfmt (max_width): Set to 80 2019-11-27 09:15:15 -05:00

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.