A little manual for Lex and Yacc
XML version, March 24th, 2000
Lex and Yacc are very useful tools for people who need to manipulate a grammar. If you are writing a compiler or an interpreter, you will have to manipulate a grammar, but this is not restrictive. Every people writing programs that have to react to certain messages, following a particular protocol (e.g. FTP or HTTP) may find Lex and Yacc useful. This little manual is a presentation of these tools, using a "learn by practice" method. Please note that English is not my native language, so I hope you will excuse my mistakes.
The content of this document and the programs included are copyright © Etienne BERNARD 1997.
1. The grammar used
2. Use of Lex in syntaxical analysis
- 2.1. First part of a Lex file: declarations
- 2.2. Regular expressions
- 2.3. Second part of a Lex file: productions
- 2.4. Third part: additional code
- 2.5. Conclusion about Lex
3. Syntaxical analysis with Yacc
- 3.1. The first part of a Yacc file
- 3.2. Second part of a Yacc file
- 3.3. Third part of a Yacc file
- 3.4. Conclusion about Yacc
4. An example: a little expression interpreter
- 4.1. The Lex part of the interpreter
- 4.2. The Yacc part of the interpreter
- 4.3. Compiling and running the example
- 4.4. A better calculator
