"Nicht Haskel 2.0" Java Compiler

Realisation of a subset of the Java Standard Compiler in the course Compiler Construction of the 4th semester Computer Science at the Duale Hochschule Stuttgart (Horb).

This project aims to provide a simplified version of the Java compiler, focusing on key language features and demonstrating the principles of compiler construction.

Realised Java syntax

• Data types: int, boolean, char
• Access modifier: public, protected, private
• Operators: = + - * % / > < >= <= == != ! && || ++ --
• Keywords: class, this, while, do, if, else, for, return, new, switch, case, break, default, :
• Statements:
  • if ... if else ... else;
  • while ... ;
  • do ... while;
  • for;
  • switch ... case ... ;
• Comments:
  • Single line: // comment
  • Multi-line: /* comment */
• Further functions:
  • All methods are overloadable
  • High maintainability and expandability through implementation of the visitor pattern
  • Logging Input and Outputs
  • Error Handling in the Semantic Check

Project Structure

src/
└── main/
    ├── java/
    │   ├── ast/              -> Defining the structure of the AST
    │   ├── bytecode/         -> Generate Java bytecode
    │   ├── main/             -> Running the compiler
    │   ├── parser/
    │   │   ├── astBuilder/   -> Builder creating the AST
    │   │   ├── generated/    -> Antlr generated grammar
    │   │   └── grammar/      -> Antlr grammar
    │   ├── semantic/         -> Running the semantic check
    │   └── visitor/          -> Visitor interface
    └── resources/
test/
└── java/
│   ├── main/                 -> MainTest, E2ETests, UtilityTests
│   ├── parser/               -> Performs tests on the parser
│   └── semantic/             -> Performs tests on the semantic check
└── resources/                -> Ressources for running the Tests

Class-Diagramm AST

Used Tools

• Maven 4.0
  • Used for automating the build process and managing dependencies.
• ANTLR4 v.13.1
  • Used to parse the input Java code into the Abstract Syntax Tree.

How to run the compiler

Possibilities

1. Start miniCompiler using make:

Make needs to be installed

cd .\src\test\ ; make clean compile-miniCompiler

2. Start miniCompiler using jar:

If you do not have the .jar, download it here or compile it using mvn package or make first

java.exe -DgenJar=bool -DgenClass=bool -jar path_to_jar\jarName.jar 'path_to_input_file.java' 'path_to_output_directory'

Example (jar needs to be in the target directory)

 java.exe -DgenJar=true -DgenClass=true -jar .\target\JavaCompiler-1.0-jar-with-dependencies.jar 'src/main/resources/input/CompilerInput.java' 'src/main/resources/output'

• set DgenJar true, to generate the jar, false for no jar

 DgenJar=true

• set DgenClass true, to generate class files, false for no class files

 DgenClass=true

How to run tests

mvn test

Or start them manually in your IDE