https://github.com/gwenn/jlemon
Lemon parser generator modified to build an SQL parser in Java
https://github.com/gwenn/jlemon
java parser-generator sql-parser
Last synced: 8 months ago
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Lemon parser generator modified to build an SQL parser in Java
- Host: GitHub
- URL: https://github.com/gwenn/jlemon
- Owner: gwenn
- License: unlicense
- Created: 2017-05-25T10:19:32.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2024-12-09T17:44:04.000Z (over 1 year ago)
- Last Synced: 2025-02-03T21:51:21.142Z (about 1 year ago)
- Topics: java, parser-generator, sql-parser
- Language: Java
- Homepage:
- Size: 615 KB
- Stars: 3
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# jlemon
A fork of the
[LEMON parser generator](https://www.sqlite.org/src/doc/trunk/doc/lemon.html)
that generates Java code and the associated [SQL parser](http://www.sqlite.org/src/artifact?ci=trunk&filename=src/parse.y).
Files `lemon.c`, `lempar.c` are extracted from SQLite v3.18.0.
[](https://search.maven.org/search?q=g:%22com.github.gwenn%22%20AND%20a:%22sqlite-parser%22)
[](https://www.javadoc.io/doc/com.github.gwenn/sqlite-parser)
## Usage
```bash
> # compile
> cc -g -O2 -o jlemon lemon.c
> # run
> jlemon .y
> # preprocess generated code
> cpp -P .j > yyParser.java
```
For example:
```bash
cc -g -O2 -o jlemon lemon.c
./jlemon src/test/java/simple/parser.y
cpp -P src/test/java/simple/parser.j > src/test/java/simple/yyParser.java
mvn test
```
Or on Windows platform:
```
cl /O2 /Fejlemon.exe lemon.c
jlemon.exe src\test\java\simple\parser.y
cl /EP /C src\test\java\simple\parser.j > src\test\java\simple\yyParser.java
```
## Generated Parser API
```java
public class yyParser {
// %extra_argument declaration
public yyParser(
ParseARG_PDECL /* Optional %extra_argument parameter */
) {
// constructor
}
public void ParseFinalize() { /* or can be renamed to %nameFinalize */
// optional (clean the stack)
}
public void Parse( /* or can be renamed to %name */
int yymajor, /* The major token code number */
ParseTOKENTYPE yyminor /* The value for the token */
){
// To be called by lexer
}
}
```
## Hack
As there is no `union` in Java, `yy%d` fields of `YYMINORTYPE` have been replaced by `yy%d()` getters and `yy%d(%type value)` setters.
But when translating code (see `translate_code`), the logic used to make the difference between a read access to a `yy%d` field and a write access is fallible.
Maybe try a code manipulator ([janino](http://janino-compiler.github.io/janino/#janino-as-a-code-manipulator)) ?
Or [javolution Union](http://javolution.org/apidocs/javolution/io/Union.html) ?
## SQL Parser
[SQLite lexer](http://www.sqlite.org/src/artifact?ci=trunk&filename=src/tokenize.c) and [SQLite parser](http://www.sqlite.org/src/artifact?ci=trunk&filename=src/parse.y) have been ported from C to Java.
The parser generates an AST.
The parser is/will be used to fix [DatabaseMetaData](https://github.com/gwenn/sqlite-jna/blob/master/src/main/java/org/sqlite/driver/DbMeta.java) implementation.
* java.sql.DatabaseMetaData.getColumns
* java.sql.DatabaseMetaData.getPrimaryKeys
* java.sql.DatabaseMetaData.getBestRowIdentifier
* java.sql.DatabaseMetaData.getCrossReference
* java.sql.DatabaseMetaData.getImportedKeys
* java.sql.DatabaseMetaData.getExportedKeys
* java.sql.DatabaseMetaData.getIndexInfo
## Lexer/Parser
- Keep track of position (line, column).
- Streamable (stop at the end of statement).
- Resumable (restart after the end of statement).
## Test
SQL 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