for loop

For Loop

A for loop iterates over a range of values or elements in a collection. Jai automatically provides the it variable containing the current value, and it_index containing the current iteration number.

Basic For Loop

    
for 1..5 print("%", it);  // Outputs: 1 2 3 4 5

Here we iterate over a number range. The it variable holds the current value, while it_index tracks which iteration we're on.

Named Iterator

    
for i: 1..5 {
    print("Value: %, Index: %\n", i, it_index);
}

You can give the iterator a custom name instead of using the default it. This improves readability, especially in nested loops.

Reverse Iteration

    
// Note: the range is still written as end..start
for < i: 5..0 {
    print("% ", i);  // Outputs: 5 4 3 2 1 0
}

The < operator before the iterator name reverses the direction of iteration.

Iterating Over Arrays

    
for array_of_things {
    print("%\n", it);
}

When iterating over arrays, values are copied into it. This means you cannot modify the original array elements this way.

Pointer Iteration

    
for *array_of_things {
    func_that_modifies(it);  // it is now a pointer to each element
}

By adding * before the collection, you iterate over pointers to each element. This allows you to modify the original data.

}

Named Loops

Named loops allow you to assign an identifier to a loop, enabling you to break or continue specific outer loops from within nested loops.

    
outer: for 0..10 {
    for 0..10 {
        if some_condition break outer;  // Exits the outer loop entirely
    }
}

Without named loops, break and continue only affect the innermost loop. Named loops give you precise control over which loop to exit or continue.

Continue with Named Loops

    
outer: for i: 0..5 {
    for j: 0..5 {
        if j == 2 continue outer;  // skips to the next iteration of outer loop
        print("(%, %) ", i, j);
    }
}