...

• a Scheme program in the file boolsimp.ss equivalent to the Java program that you are required to write;
• a Java "stub" file boolSimp.dj1 that defines a composite hierarchy of "abstract syntax" tree classes rooted in the class Form representing boolean expressions;
• a Java library file Parser.java contain a class Parser with
  • a read() method that reads a boolean expression represented in "Scheme form" and returns the corresponsing Java Form abstract syntax tree and
  • a (commented out) simplifyreduce() method that composes the visitors you must write in boolSimp.dj1 to simplify reduce whatever formula the Parser instance contains to simplified form.
• a Java "stub" test file boolSimpTest.java that includes some rudimentary tests of the code in the boolSimp.dj1 stub file.

...

The Java abstract syntax classes include a separate composite hierarchy (called IfForm for representing boolean expression as conditionals (the type ifExp in boolsimp.ss). This representation includes only three concrete variant classes, making it much easier to write the visitors that perform normalization, evaluation, and clean-up.

The visitor pattern is a straightforward but notationally involved alternative to the interpreter pattern.. You can mechanically translate interpreter pattern code to visitor pattern code. (Perhaps IDEs like Eclipse should support such transformations.) The interpreter solution to this assignment is easier to write than the visitor solution described in the preceding program description. If you are still learning Java mechanics, you are encouraged to write an interpreter solution first and translate it (if you can) to visitor form. A perfect interpreter solution will only be penalized 15% versus a perfect visitor solution. If you submit an interpreter solution, your program must conform to class signatures given in the interpreter pattern support code below (just as a visitor solution must conform to the class signatures given in the visitor pattern code below).

The interpreter version of the support code replaces the ConvertToIf, Normalize, HeadNormalize, Evaluate, and Print visitors by methods named convertToIf, normalize, headNormalize, eval, and print.

Support Code

Here are the links for the files:

• boolsimp.ss is the reference Scheme program.
• BoolSimp.dj1 is a stub program for a visitor solution.
• BoolSimpTest.java is a stub test file for a visitor solution.
• Parser.java is a parser file for a visitor solution.
• InterpBoolSimp.dj1 is a stub program for an interpreter solution.
• InterpBoolSimpTest.javaboolsimp.ss is a stub test file for an interpreter solution.
• InterpParser.java is a parser file for an interpreter solution.

InterpParser.java is distinct from Parser.java because the code for the reduce method embedded in the parser is different in the two versions.

Sample Input Files

The following files contain large formulas that can be reduced by your simplifier. Only the file named bigData require a larger thread stack size than the default on my laptop. I used the JVM argument -Xss64M for the Interactions JVM to get the bigData files to run.

...