CS 453 Programming Assignment #3 — MeggyJava CheckButton Compiler (Control Flow, Parser Generators, and ASTs)

Java, and therefore MeggyJava allows int, byte mixed type expressions for addition, subtraction, comparison, and negation. This is relevant for type checking as well as code generation. Note that the MeggyJava grammer allows only for byte type operands to be used by the multiplication operator.

The Assignment

• modify your PA2 lexer to handle one-line and multi-line comments in Java,
• modify your PA2 parser so that it is generated by Happy (LALR parser generator for Haskell),
• modify your Happy grammar specification so that it does syntax-directed construction of an Abstract Syntax Tree (AST) instead of doing code generation,
• perform type checking for the PA2 grammar in a function that accepts an AST as input and calls error with a reasonable message if there is a type error,
• perform code generation to AVR assembly code for the PA2 AST nodes with another function, and
• incrementally add the PA3 grammar rules to the parser, implement the rules AST creation, type checking, and code generation.

We will cover shift-reduce parsing and parser generators for shift-reduce parsers starting March 3rd. We recommend that you start by extending your lexer, developing and AST data structure, and developing functions that generate code for your AST and perform type checking. A significant portion of the assignment can be completed before including the parser generated by Happy and your grammar specification with actions that create the AST. START NOW!! This assignment will take time.

Example ASTs

Example ASTs of some test cases are here:

• Byte.java.ast for Byte.java
• CondExpr.java.ast for CondExpr.java
• If.java.ast for If.java
• IfStmt.java.ast for IfStmt.java

Grading Details

    happy MJParserPA3.y -i
    ghc --make MainPA3.hs -o mjc
    mjc TestCase.java
    java -jar MJSIM.jar -b -f TestCase.java.s > t1

    javac TestCase.java
    java TestCase > t2
    diff t1 t2
   

The input files can be any PA3 MeggyJava program. The output file named InputFile.java.s should be an AVR assembly program that using the provided build process could run on the MeggyJr device. Additionally, the InputFile.java.s file must be such that we can run it through the AVR simulator, MJSIM.jar. See the Meggy Sim instructions for usage notes.

We highly recommend you use the regression script (regress.sh) that was covered in the third week's recitation. Create multiple test cases, put them in the WorkingTestCases/ subdirectory and test your mjc compiler against the Java-only output.

Assembly (.s) programs have a prolog and epilog. For PA3 and later assignments, we will let you provide your own input files for these to avoid any grading issues. Make sure to include any files you need in your tar ball.

Execute MJSIM.jar for a list of available instructions. For more details about the instructions see the 06-AVR.txt notes.

For this assignment, there will be no lexer errors, but there will be examples with type errors. Your compiler should catch type errors and print out a reasonable message. We will be manually comparing your messages to those generated by by the Java compiler, javac.

You will need to submit a video of your MeggyJr with a MeggyJava program that only demonstrates the features in the PA2 and PA3 grammars. The picture should be named demoPA3.something, where something is .mov or whatever video format you used for PA1. You can talk during the demo.

Submitting the Assignment

• Create a README file that includes your usernames, email addresses, and any information you want the TA to have before grading your assignment. E.g., this part is not working due to..., a favorite quote or joke to amuse the TA, etc.
• The revision-control.txt file should include output from the following:

  svn log
  svn info
      

  The output should be from subversion or similar output from any other revision control tool.
• Put all your files into a tar ball.

    tar cvf PA3.tar README revision-control.txt Lexer.hs MJParserPA3.y MainPA3.hs 
    

• The PA3 demo videos page has been set up. You can now upload your demoPA3.mov to the page. We need one video per group.
• Submit your PA3.tar file through the Checkin tab off the course webpage. EACH person should submit a tar ball. Of course, we expect that tar balls within a group will be identical. Testing the correctness of your mjc is up to you.
• Make sure that your PA3.tar file also includes your avr files (avrF.rtl.s annd avrH.rtl.s). We will not be providing the avr files for the grading.
• Your PA3.tar should not include ANY folders.

Grading

• 5% README file
• 5% revision-control.txt file
• 5% demo file
• 15% Compiler detects first type error for PA3 grammar productions
• 70% Compiler generates AVR executable by MJSIM.jar for the PA3 MeggyJava grammar.

Late Policy