Control Flow¶

Note: Only if/else chains and while loops are currently supported. C-style for loops, for-in loops, range loops, and the ternary operator are not supported by the compiler.

Introduction to Control Flow¶

Control flow structures determine the order in which statements are executed in a program. They allow for conditional execution (if/else) and repeated execution (loops) of code blocks. In firescript, control flow constructs use curly braces {} to define code blocks.

Conditional Statements¶

Conditional statements execute different blocks of code depending on whether a specified condition evaluates to true or false. firescript supports if, else if, and else statements.

Basic If Statement¶

The simplest form executes a block of code only if the condition is true:

if (condition) {
    // Code executed only if condition is true
}

Example:

int age = 18;
if (age >= 18) {
    print("You are eligible to vote");
}

If-Else Statement¶

You can specify an alternative block of code to execute when the condition is false:

if (condition) {
    // Code executed if condition is true
} else {
    // Code executed if condition is false
}

Example:

int score = 65;
if (score >= 70) {
    print("Pass");
} else {
    print("Fail");
}

If-Else If-Else Chains¶

For multiple conditions, you can use else if:

if (condition1) {
    // Executed if condition1 is true
} else if (condition2) {
    // Executed if condition1 is false and condition2 is true
} else if (condition3) {
    // Executed if condition1 and condition2 are false and condition3 is true
} else {
    // Executed if all conditions are false
}

Example:

int grade = 85;

if (grade >= 90) {
    print("A");
} else if (grade >= 80) {
    print("B");
} else if (grade >= 70) {
    print("C");
} else if (grade >= 60) {
    print("D");
} else {
    print("F");
}

Nested Conditional Statements¶

Conditional statements can be nested within other conditional statements:

bool hasDiscount = true;
int totalAmount = 120;

if (totalAmount > 100) {
    if (hasDiscount) {
        print("You qualify for a 15% discount");
    } else {
        print("You qualify for a 10% discount");
    }
} else {
    print("No discount available");
}

Boolean Expressions in Conditions¶

Conditions can use various boolean operators:

Comparison operators: ==, !=, >, <, >=, <=
Logical operators: && (AND), || (OR), ! (NOT)

Example:

int age = 25;
bool hasLicense = true;

if (age >= 18 && hasLicense) {
    print("You can drive");
}

if (!(age < 18 || !hasLicense)) {
    print("Also, you can drive"); // Equivalent to the above
}

Loops¶

Loops allow for repeated execution of a block of code. firescript supports while loops and plans to support various forms of for loops in the future.

While Loops¶

A while loop repeatedly executes a block of code as long as a specified condition is true:

while (condition) {
    // Loop body: code executed repeatedly as long as condition is true
}

Example:

int count = 0;
while (count < 5) {
    print(count);
    count = count + 1;
}
// Outputs: 0, 1, 2, 3, 4

Infinite Loops¶

A while loop with a condition that is always true creates an infinite loop. These should be used with caution and should include a break statement:

while (true) {
    // This will run forever unless broken
    if (someCondition) {
        break; // Exit the loop
    }
}

Loop Control Statements¶

The following statements can control loop execution:

break - Immediately exits the loop
continue - Skips the rest of the current iteration and starts the next one

Example:

int i = 0;
while (i < 10) {
    i = i + 1;

    if (i == 3) {
        continue; // Skip the rest of this iteration
    }

    if (i == 8) {
        break; // Exit the loop
    }

    print(i);
}
// Outputs: 1, 2, 4, 5, 6, 7

Combining Loops and Conditionals¶

Loops and conditional statements can be combined to create powerful control flows:

int[] numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
int sum = 0;
int i = 0;

while (i < numbers.length) {
    if (numbers[i] % 2 == 0) {
        sum = sum + numbers[i]; // Add only even numbers
    }
    i = i + 1;
}

print(sum); // Outputs: 30 (2 + 4 + 6 + 8 + 10)

Future Control Flow Features¶

The following control flow features are planned but not yet implemented in the current compiler:

C-style For Loops¶

// Future syntax
for (int i = 0; i < 5; i++) {
    print(i);
}

For-In Loops¶

// Future syntax
string[] fruits = ["apple", "banana", "cherry"];
for (string fruit : fruits) {
    print(fruit);
}

Range Loops¶

// Future syntax
for (int i : range(5)) {
    print(i); // 0, 1, 2, 3, 4
}

for (int i : range(2, 8)) {
    print(i); // 2, 3, 4, 5, 6, 7
}

for (int i : range(1, 10, 2)) {
    print(i); // 1, 3, 5, 7, 9
}

Ternary Operator¶

// Future syntax
int max = ternary a > b then a else b;

Switch Statements¶

// Future syntax
switch (value) {
    case 1:
        // code for case 1
        break;
    case 2:
        // code for case 2
        break;
    default:
        // default code
}

Best Practices¶

Keep conditions simple: Split complex conditions into multiple variables for better readability.
Avoid deep nesting: Too many nested if/else statements make code hard to follow. Consider refactoring deeply nested code.
Be careful with while loops: Always ensure that the condition will eventually become false to avoid infinite loops.
Use appropriate loop types: Once implemented, choose the right loop for the task: while for unknown iteration counts, for for counting, and for-in for collections.

Implementation Status¶

The current firescript compiler supports:

✅ if/else/else if conditional statements
✅ while loops
✅ break and continue statements

Not yet implemented:

❌ C-style for loops
❌ for-in loops
❌ Range-based loops
❌ Ternary operator
❌ switch/case statements