77ce4780d9
Currently we have this:
program.alloc_cursor_id(Option<String>, CursorType)`
where the String is the table's name or alias ('users' or 'u' in
the query).
This is problematic because this can happen:
`SELECT * FROM t WHERE EXISTS (SELECT * FROM t)`
There are two cursors, both with identifier 't'. This causes a bug
where the program will use the same cursor for both the main query
and the subquery, since they are keyed by 't'.
Instead introduce `CursorKey`, which is a combination of:
1. `TableInternalId`, and
2. index name (Option<String> -- in case of index cursors.
This should provide key uniqueness for cursors:
`SELECT * FROM t WHERE EXISTS (SELECT * FROM t)`
here the first 't' will have a different `TableInternalId` than the
second `t`, so there is no clash.
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.