Simple Kotlin_to_JAVA Compiler :: Using ANTLR4

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Introduction

This project is assignment for Sungkyunkwan University's PL class
It provides the ability to translate some of Kotlin's basic syntax into JAVA Language
(Spring 2019)

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Structure & Simple Discription

Lexer&Parser implemted by Antlr4

KotlinLexer.g4
KotlinParser.g4
KotlinLexer.java
KotlinParser.java
KotlinParserBaseListener.java
KotlinParserListener.java

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JAVA files Based on Antlr4 Lexer&Parser

1. Kotlin2Java.java : Main Class

Main class of this project. It starts program flow like

1. receives input file & outpu-t file name from commandline argument. If missing, exit program
2. Antlr4 creates parse tree, walker and attaches them to KotlinListener.
3. Check if output file name is in commandline argument. If not, output file name is automatically fixed as "output.java"
4. Walker walks from root using listner.

2. KotlinListener.java : Listener Class

Listener class, contains functions that respond when entering and exiting each token.
Structure is automatically implemented by Antlr4
It manages tokens using stack.
Whenever enter a token, it is entered into the stack.
Also it handles expressions using KotlinExprForm

3. KotlinExprForm.java : Expr form Class

Super class for variable expression handling classes.
Its child class is as follow:

1. KotlinCallExprForm : Handling callable expressions
2. KotlinDotExprForm : Handling expressions containing dot(sign of decimal, properties, etc..)
3. KotlinForExprForm : Handling 'for' expressions
4. KotlinIdxExprForm : Handling array expressions
5. KotlinIExprForm : Handling 'is' expressions
6. KotlinIfExprForm : Handling 'if' expressions
7. KotlinWhileExprForm : Handling 'while' expressions

4. KotlinExprStacks.java : Expression Stack Class

This class is for stacks managing expressions

5. KotlinFunDeclForm.java : Function Expr Class

This class handles function structures.

6. KotlinConst.java : Const Class

Const variables are defined in this class

7. KotlinIDStackJob.java : Id stack manager Class

8. KotlinMultiVarDeclForm.java : Parenthesis making Class

9. KotlinUtils.java : Util Class

This class contains some functions used for several situations.

1. cngType : Converts type of variables to make JAVA compiler can read
2. chkType : Checks type of variables, especially listOf, and call chkDetail function
3. chkDetail : Specifically inferences the type of variable - Integer, String, Double
4. cngListOf : Changes listOf structure into square bracket in specific case.

10. KotlinPrefExprForm : UNUSED