Compile using blc and run ./out.

main :: fn () s32 {
    // Declare slice variable, no allocation is done here, my_slice.len is zero
    // and my_slice.ptr is null.
    my_slice: []s32;

    // Use of the 'alloc_slice' function to allocate memory block for 10 numbers.
    alloc_slice(&my_slice, 10);

    // Release memory allocated by 'alloc_slice' when it's no longer needed. Defer
    // statement will execute 'free_slice' function at the end of current 
    // scope.
    defer free_slice(&my_slice);

    // Len is now set to 10.
    print("my_slice.len = %\n", my_slice.len);

    // Ptr is pointer to the allocated memory.
    print("my_slice.ptr = %\n", my_slice.ptr);

    // The 'alloc_slice' will set allocated elements to 0.
    print("my_slice: %\n", my_slice);

    // Fill the slice with numbers
    loop i := 0; i < my_slice.len; i += 1 {
        // Use [N] to access elements.
        my_slice[i] = i;

    print("my_slice: %\n", my_slice);

    // Array can be implicitly converted to slice, in such case no 'alloc_slice'
    // or 'free_slice' is needed. Actual data will stay in original array
    // location, slice in such case acts only like an 'interface' to the original
    // array.

    array := [4]s32.{0, 1, 2, 3};
    slice_from_array : []s32 = array;

    print("slice_from_array = %\n", slice_from_array);

    // This implicit conversion can be useful in function calls. We can now call
    // function 'gimme_slice' with any slice containing numbers of s32 type. If 
    // you try this with regular arrays you will be able to pass only arrays of 
    // the exact same size defined in array type of the function argument. 
    // Passing of array will cause copying of whole array on callee side, passing 
    // slice is much more effective, since it's only len and ptr to data.

    // Due to implicit conversion from array to slice we can call 'gimme_slice'
    // function directly with an array argument, it will be passed into the 
    // function as a slice.

    return 0;

gimme_slice :: fn (slice: []s32) {
    print("Slice has % elements.\n", slice.len);