1. ANTLR Andrew Pangborn & Zach Busser

2. ANTLR in a Nutshell ANother Tool for Language Recognition generates lexers generates parsers (and parse trees)‏ Java-based, but has runtime implementations in other languages like python, javascript, c, c#, obj-c An LL(*) parser EBNF grammar notation

3. ANTLR Features Hierarchical lexical rules Abstract Syntax Tree generation Inline code execution Tree grammars

4. ANTLR Pros Target languages besides Java – C, python, Javascript, etc. LL(*) - not limited to 1 lookahead token Simpler to debug than LALR grammars (no cryptic shift-reduce / reduce-reduce errors) ANTLRWorks

5. ANTLR Shortcomings An LL parser – cannot support left-recursive grammars like YACC or PJ2 Recursive descent approach not great for efficiency No mechanism for specifying operator precedence

6. Getting started with ANTLR http://www.antlr.org/wiki/display/ANTLR3/FAQ+- +Getting+Started http://www.antlr.org/wiki/display/ANTLR3/FAQ+- +Getting+Started

7. Demo Time! A simple 4-function expression parser 4-function expression evaluator AST generation example

8. References http://www.corriganjc.net/weblog/archives/2007/06/ the_antlr_trini.html http://www.corriganjc.net/weblog/archives/2007/06/ the_antlr_trini.html http://www.antlr.org/wiki/display/ANTLR3/ANTLR+v 3+documentation http://www.antlr.org/wiki/display/ANTLR3/ANTLR+v 3+documentation