chore: claude.md (#11)

Author: h3n4l

CLAUDE.md

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+# Parser Development Guide
+
+This project contains multiple SQL parsers built with ANTLR 4 for different database dialects.
+
+## Parser Structure
+
+Each parser is organized in its own directory containing:
+- ANTLR grammar files (`.g4`)
+- Generated Go parser/lexer files
+- Test files and examples
+- Individual `Makefile` for build/test commands
+
+## Generating Parsers
+
+**IMPORTANT**: Always generate the parser after completing any grammar changes.
+
+```bash
+cd <parser-directory>/
+make build
+```
+
+The `make build` command:
+1. Runs ANTLR to generate Go code from `.g4` grammar files
+2. Creates lexer, parser, listener, and visitor files
+3. Must be run before testing after any grammar modifications
+
+## Running Tests
+
+**IMPORTANT**: Always run golang tests after generating the parser.
+
+```bash
+cd <parser-directory>/
+make test
+```
+
+## Development Workflow
+
+1. **Make grammar changes** to `.g4` files
+2. **Generate parser** using `make build` in the specific parser directory
+3. **Run tests** using `make test` to verify changes
+4. **Add test cases** in the `examples/` directory for new features
+
+## Notes
+
+- Each parser directory has its own `Makefile` with `build` and `test` targets
+- The `make all` target in each directory runs both build and test
+- Always regenerate parsers after modifying grammar files
+- Test files are located in each parser's `examples/` directory