The materials in this folder are designed to serve two primary purposes:

To address Course Learning Objective 9: "Implement an interpreter for a simple but realistic language."
To provide a review of (or introduction to) the front end implementation that was developed during CS 321, including syntax and static analysis. This review is necessary because the front end components will be used for one or more graded assignments in later weeks to address Course Learning Objective 10: "Implement a code generator for a simple but realistic language, producing native code for a real machine."

Outline/study plan:

Abstract syntax:

Review 0-AST-Notes.txt and the code in the AST folder. Look at examples from ast/* to review typical layout and structure. View, compile ("make") and run Main ("java Main"), explaining format of output generated.

Syntax analysis:

Review 1-Parser-Notes.txt and the code in the Parser folder. Review Parser.jj. Compile and run Parser on test?.prog files, reflecting on output.

Static analysis:

Review 2-Static-Notes.txt and the code in the Static folder. Compile and run Static on test?.prog files, commenting on annotations that appear in generated output. Consider review of specific implementations (e.g., matchTypes, ArithBinExpr, etc...)

... transition from review to new material at this point ...

Static analysis for Interpreter:

Review 3-Interp-Notes.txt, and discuss basic representation and implementation strategies, including globals and locals arrays, slot numbers, and frameSize. Review sample outputs. Review code in StaticInterp, highlighting additional code that calculates these new attributes. Illustrate the use of "diff -C 2 -r Static StaticInterp" to identify and walk through the changes that have been made.

Interpreter:

Move in to Interp. Demonstrate the interpreter on a simple example. Demonstrate "java Interp < test4.prog" and relate to path in AST. Walk through examples for IntLit, Add, Eql, and Call.

Exercise: replace stubs for eval() implementations with working code. (Do not worry about floating point.) Use a simple "void main() { print expr; }" form for testing.

Walk through sample solutions.

Return to code, discuss handling of statements. Walk through examples for Return, Block, Print, and Locals.

Exercise: replace stubs for exec() implementations with working code. Use test?.prog examples for testing, as well as other examples devised specifically for the purpose of testing.