Enable method overloading and overriding

[AprupKale]

Enable running multiple classes in java-slang.

Enable method overloading and overriding to support code as follows:

public class Main {
  public void f(int x) {
    System.out.println("Instance int: " + x);
  }
  public void f(double x) {
    System.out.println("Instance double: " + x);
  }
  public static void main(String[] args) {
    Main obj = new Main();
    obj.f(5);
    obj.f(5.5);
  }
}

and

class Parent {
  public static void staticMethod() {
    System.out.println("Parent static method");
  }
  public void instanceMethod() {
    System.out.println("Parent instance method");
  }
}

class Child extends Parent {
  public static void staticMethod() {
    System.out.println("Child static method");
  }
  public void instanceMethod() {
    System.out.println("Child instance method");
  }
}

public class Main {
  public static void main(String[] args) {
    Parent.staticMethod(); // Parent static method
    Child.staticMethod(); // Child static method
    Parent ref = new Child();
    ref.instanceMethod(); // Child instance method
  }
}

[github-actions]

Coverage report

Caution

Test run failed

St.❔	Category	Percentage	Covered / Total
🟡	Statements	72.3% (-1.27% 🔻)	7381/10209
🔴	Branches	58.78% (-1.1% 🔻)	2461/4187
🟡	Functions	68.86% (-0.66% 🔻)	1316/1911
🟡	Lines	73.16% (-1.33% 🔻)	6947/9496

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🟡	... / expression-extractor.ts	67.35% (-10.88% 🔻)	58.51% (-10.72% 🔻)	86.67% (-6.19% 🔻)	66.43% (-11.07% 🔻)
🟡	... / index.ts	70.56% (-1.12% 🔻)	47.31% (-2.31% 🔻)	91.67% (-3.99% 🔻)	79.47% (-1.59% 🔻)
🟢	... / compiler.ts	100%	83.33% (-9.52% 🔻)	100%	100%
🟢	... / symbol-table.ts	91.09% (-2.81% 🔻)	67.39% (-12.02% 🔻)	100%	90.58% (-3.05% 🔻)
🟡	... / code-generator.ts	68.39% (-19.85% 🔻)	61.04% (-16.58% 🔻)	65.43% (-27.9% 🔻)	69.23% (-19.23% 🔻)

Test suite run failed

Failed tests: 0/1115. Failed suites: 1/64.

  ● Test suite failed to run

    src/ast/__tests__/expression-extractor.test.ts:1078:27 - error TS2322: Type '{ kind: "CastExpression"; type: string; expression: { kind: "Literal"; literalType: { kind: "DecimalIntegerLiteral"; value: string; }; location: any; }; location: any; }' is not assignable to type 'VariableInitializer | undefined'.
      Object literal may only specify known properties, and 'type' does not exist in type 'CastExpression'.

    1078                           type: "char",
                                   ~~~~

      src/ast/types/blocks-and-statements.ts:127:3
        127   variableInitializer?: VariableInitializer;
              ~~~~~~~~~~~~~~~~~~~
        The expected type comes from property 'variableInitializer' which is declared here on type 'VariableDeclarator'
    src/ast/__tests__/expression-extractor.test.ts:1147:27 - error TS2322: Type '{ kind: "CastExpression"; type: string; expression: { kind: "Literal"; literalType: { kind: "DecimalFloatingPointLiteral"; value: string; }; }; location: any; }' is not assignable to type 'VariableInitializer | undefined'.
      Object literal may only specify known properties, and 'type' does not exist in type 'CastExpression'.

    1147                           type: "int",
                                   ~~~~

      src/ast/types/blocks-and-statements.ts:127:3
        127   variableInitializer?: VariableInitializer;
              ~~~~~~~~~~~~~~~~~~~
        The expected type comes from property 'variableInitializer' which is declared here on type 'VariableDeclarator'

Report generated by 🧪jest coverage report action from 805b448

[martin-henz]

/gemini review

[gemini-code-assist]

Code Review

This pull request implements support for SwitchStatement and CastExpression, covering grammar updates, AST extraction, type checking, and bytecode generation. It also enhances method invocation to support overloading, overriding, and super calls, and enables the compiler to handle multiple class files. Feedback highlights several critical issues, including incorrect usage of the in operator and filter method in TypeScript, flawed JVM offset patching for switch instructions, and a missing string collision check in switch statements. Additionally, the reviewer identified logic errors in the final method override checks and inconsistent package naming conventions that could lead to lookup failures.

[gemini-code-assist]

In JavaScript/TypeScript, the in operator checks for the existence of a property name in an object. For an array, it checks for indices (e.g., '0', '1'), not values. Use Array.prototype.includes() instead.

Suggested change

	if (!(fromType in ['J', 'D']) && toType in ['J', 'D']) {
	return 1
	} else if (!(toType in ['J', 'D']) && fromType in ['J', 'D']) {
	if (!['J', 'D'].includes(fromType) && ['J', 'D'].includes(toType)) {
	return 1
	} else if (!['J', 'D'].includes(toType) && ['J', 'D'].includes(fromType)) {
	return -1

[gemini-code-assist]

The filter method returns a new array and does not mutate the original one. You must assign the result back to candidateMethods.

Suggested change

	candidateMethods.filter(method =>
	method.className == cg.symbolTable.queryClass(cg.currentClass).parentClassName)
	candidateMethods = candidateMethods.filter(method =>
	method.className == cg.symbolTable.queryClass(cg.currentClass).parentClassName)

[gemini-code-assist]

The filter result is ignored here. Assign it back to candidateMethods.

Suggested change

	candidateMethods.filter(method =>
	method.className == cg.currentClass)
	candidateMethods = candidateMethods.filter(method =>
	method.className == cg.currentClass)

[gemini-code-assist]

The patching logic for switch offsets is incorrect.

1. JVM offsets for TABLESWITCH and LOOKUPSWITCH are 4-byte signed integers. Assigning to a single index in cg.code (which is a byte array) only updates the last byte of the offset.
2. The mapping logic seems reversed or misaligned: caseLabelIndex[0] is being patched with the offset of the last label in caseLabels.
3. caseLabelIndex contains indices relative to the start of the code, but the mapping should correspond to the specific case values or hash codes defined in the switch table.

[gemini-code-assist]

Switching on a String based only on hashCode is insufficient because different strings can have the same hash code (collisions). You must implement a secondary check using String.equals() to ensure correctness, as noted in your TODO.

[gemini-code-assist]

This loop iterates through the scope stack (this.tables), but in your implementation, parent classes are not ancestors in this stack; they are stored as siblings in the root table. To correctly check if a method overrides a final method in a superclass, you should follow the parentClassName hierarchy and look up the corresponding class in the root table.

[gemini-code-assist]

Remove this console.log statement before merging.

[gemini-code-assist]

Remove this console.debug statement.

[gemini-code-assist]

There is an inconsistency in package naming. Here you are using dots (e.g., java.lang/), while in handleImports (line 152) you use slashes (e.g., java/lang/). JVM internal names and descriptors typically use slashes. This inconsistency will likely cause queryClass to fail when looking up library classes.