[ahmed7p]

Linked Issues

#321

Description

This PR adds support for static local variables (static var / static final)

Key Changes:

• Parser & Expr:
  • Extended EVar and EFinal expressions to accept an optional isStatic flag.
  • Added support for parsing static var and static final declarations.
  • Fixed variable declaration parsing and commas handling when using final a,b,c declarations.
  • Added EInvalidStaticLocalInit error type.
• Interp:
  • Implemented unique storage mapping ($clsName#$funcName#$varName) in scriptInterp.variables so static locals retain their state across function calls and loop executions.
  • Updated function scoping (currentFunction, oldFunctionName) during EFunction execution to ensure accurate context tracking.
• Validation & Safety Checks:
  • Added strict checks to prevent invalid initializers (e.g., blocking switch expressions, this, super, instance fields, and non-static local variables).
  • Added conflict validation against existing class static fields.
  • Added validateAssignment to block expressions that do not return values during variable assign.

Examples

Comprehensive Usage Examples:

function testStaticLocals() {
    // 1. Basic state persistence across function calls
    static var hitCount = 0;
    hitCount++; 
    trace('Hits: $hitCount'); // Persists and increments values across re-entries

    // 2. Using static final for read-only configuration/constants
    static final MAX_LIMIT = 100;
    trace('Max limit is: $MAX_LIMIT');

    // 3. Using compound assignments (+=, -=, etc.)
    static var score = 10;
    score += 5; // Properly updates and persists state in scriptInterp.variables
    trace('Score: $score');

    // 4. Multiple static declarations with comma separation
    static var a = 1, b = 2, c = 3;
    a += 10;
    trace('a: $a, b: $b, c:$c');
}

function getModSettings() {
    // Initialized and cached on first call
    static var cachedConfig:Map<String, Dynamic> = null;
    
    if (cachedConfig == null) {
        cachedConfig = CoolUtil.parseJson(Assets.getText('assets/data/global-mod-config.json'));
    }
    return cachedConfig;
}

function recordSessionStats(noteMissed:Bool) {
    // Persists across different songs in Story Mode or multiple retries
    static var totalSessionMisses = 0;
    
    if (noteMissed) {
        totalSessionMisses++;
        if (totalSessionMisses >= 10) {
            triggerSecretAchievement();
        }
    }
}

2. Error Handling (Invalid Initializer):

function staticLocalErrors(val:Int) {
    var normalLocal = 10;

    // 1. Error: Using a non-static local variable as an initializer
    // Throws: Cannot initialize static variable "staticLocalErrors_x": cannot use local variable "normalLocal" as an initializer
    static var x = normalLocal; 

    // 2. Error: Using "this" as an initializer
    // Throws: Cannot initialize static variable "staticLocalErrors_y": cannot use "this" as initialization
    static var y = this; 

    // 3. Error: Using "super" as an initializer
    // Throws: Cannot initialize static variable "staticLocalErrors_z": cannot use "this" as initialization
    static var z = super; 

    // 4. Error: Using an instance field as an initializer
    // Throws: Cannot initialize static variable "staticLocalErrors_w": cannot use instance field "someInstanceField" as an initializer
    static var w = someInstanceField; 

    // 5. Error: Using a switch expression as an initializer
    // Throws: Cannot initialize static variable "staticLocalErrors_v": cannot use a switch expression as an initializer
    static var v = switch (val) {
        case 1: "One";
        default: "Other";
    }; 

    // 6. Error: Using an expression that does not return a value (e.g., while loop)
    // Throws: Cannot assign an expression that does not return a value.
    var u = while (false) {}; 

    // 7. Error: Name conflict with an existing local static field
   static var existingStaticField = 100; 
    // Throws: The expanded name of static local "staticLocalErrors_existingStaticField" conflicts with another static field
    static var existingStaticField = "serious_car"; 
}

[nykwono]

good