This document discusses building a compiler for a simple language called "Awesome" that targets the Java Virtual Machine (JVM). It recommends writing a stub code generator first for quick feedback before building the full compiler. The compiler will use Scala parser combinators to parse the input into an abstract syntax tree (AST) and then walk the AST to generate equivalent JVM bytecode using the Bytecode Engineering Library (BCEL). The document outlines the overall compiler architecture and next steps to expand the language features supported by the compiler.

1. Open Source Compiler Construction (for the JVM) Tom Lee Shine Technologies OSCON Java 2011

3. About Scala

4. About Apache BCEL

5. A Generalized Compiler Architecture

6. Introducing “Awesome”

7. Writing a Stub Code Generator for “Awesome”

8. Abstract Syntax Trees (ASTs)

9. Parsing “Awesome” with Scala

10. What Next?

12. Allows interop between various source languages.

13. JVM bytecode is architecture-independent.

15. Apache / Harmony

16. OpenJDK

17. Many more...

20. Pattern matching

21. Classes & traits

24. “Bytecode Engineering Library”

25. Emit JVM bytecode with a reasonably straightforward API.

29. Code Generator traverses the AST to produce target code.

30. Introducing “Awesome” program ::= ( expression ';')* expression ::= sum sum ::= product (('+' | '-') product )* product ::= number (('*' | '/') number )* number ::= /[0-9]+/ The “Awesome” compiler will generate JVM bytecode to display each parsed expression. (Awesome, eh?)

33. We'll make the code generator do “real” stuff later.

35. Constructed by the parser.

40. The “Awesome” Grammar Revisited program ::= ( expression ';')* expression ::= sum sum ::= product (('+' | '-') product )* product ::= number (('*' | '/') number )* number ::= /[0-9]+/

42. Conditional logic?

43. For/while loops?

44. Function calls?

46. Use Scala parser combinators to build an AST from your input.

47. Update the code generator to walk the AST, emitting equivalent bytecode for each node using BCEL.

48. Iterate & add new features!

49. That's All, Folks! Shine Technologies www http://www.shinetech.com github shinetech twitter @realshinetech Tom Lee www http://tomlee.co email me@tomlee.co github thomaslee twitter @tglee All code from this presentation will be available from http://github.com/thomaslee/oscon2011-awesome