7ca84ee5b0
sqlite uses [fixed-size](https://github.com/sqlite/sqlite/blob/7fc6e6a27 26e650d3b82c6d3683bdbdc10e02467/tool/lempar.c#L238) array for `yystack` and grow stack if needed. Let replace `vec` with `smallvec` in rust version. after: ```sh sqlparser-rs parsing benchmark/sqlparser::select time: [564.19 ns 565.63 ns 567.18 ns] change: [-11.514% -11.288% -11.067%] (p = 0.00 < 0.05) Performance has improved. Found 4 outliers among 100 measurements (4.00%) 1 (1.00%) low mild 3 (3.00%) high mild sqlparser-rs parsing benchmark/sqlparser::with_select time: [1.9812 µs 1.9861 µs 1.9914 µs] change: [-7.5226% -7.3080% -7.0858%] (p = 0.00 < 0.05) Performance has improved. Found 5 outliers among 100 measurements (5.00%) 1 (1.00%) low mild 4 (4.00%) high mild ``` Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com> Closes #1999
LEMON parser generator modified to generate Rust code.
Lemon source and SQLite3 grammar were last synced as of July 2024.
Unsupported
Unsupported Grammar syntax
%token_destructor: Code to execute to destroy token data%default_destructor: Code for the default non-terminal destructor%destructor: Code which executes whenever this symbol is popped from the stack during error processing
https://www.codeproject.com/Articles/1056460/Generating-a-High-Speed-Parser-Part-Lemon https://www.sqlite.org/lemon.html
SQLite
SQLite lexer and SQLite parser have been ported from C to Rust. The parser generates an AST.
Lexer/Parser:
- Keep track of position (line, column).
- Streamable (stop at the end of statement).
- Resumable (restart after the end of statement).
Lexer and parser have been tested with the following scripts:
- https://github.com/bkiers/sqlite-parser/tree/master/src/test/resources
- https://github.com/codeschool/sqlite-parser/tree/master/test/sql/official-suite which can be updated with script in https://github.com/codeschool/sqlite-parser/tree/master/test/misc
TODO:
- Check generated AST (reparse/reinject)
- If a keyword in double quotes is used in a context where it cannot be resolved to an identifier but where a string literal is allowed, then the token is understood to be a string literal instead of an identifier.
- Tests
- Do not panic while parsing
- CREATE VIRTUAL TABLE args
- Zero copy (at least tokens)
Unsupported by Rust
#linedirective
API change
- No
ParseAlloc/ParseFreeanymore
Features not tested
- NDEBUG
- YYNOERRORRECOVERY
- YYERRORSYMBOL
To be fixed
- RHS are moved. Maybe it is not a problem if they are always used once. Just add a check in lemon...
%extra_argumentis not supported.- Terminal symbols generated by lemon should be dumped in a specified file.
Raison d'être
-
lemon_rust does the same thing but with an old version of
lemon. And it seems not possible to useyystackas a stack because items may be access randomly and thetop+1item can be used. -
lalrpop would be the perfect alternative but it does not support fallback/streaming (see this issue) and compilation/generation is slow.
Minimum supported Rust version (MSRV)
Latest stable Rust version at the time of release. It might compile with older versions.