dynamic_arrays.bl

// Dynamic arrays

/*
    Until now we've used only arrays with fixed size known in compile time,
    but sometimes we need array size to be changed in runtime. In such case 
    we can use builtin dynamic array type.

    Dynamic arrays can be extended in runtime, memory allocated to store all
    values is dynamically reserved on heap as needed.
*/

// First of all we must load API functions for dynamic array. The #load hash
// directive can be used to "include" other source files.
#load "std/array.bl"

main :: fn () s32 {
    // Now we create new dynamic array to store numbers. No heap alloacation 
    // is done here, we only specify element type of the array. As it's with 
    // regular static arrays or slices, we can access the element count via 
    // .len and allocated memory block via .ptr member. Compared to static
    // arrays, there is additional member .allocated telling us how many
    // elements could array handle till next allocation is needed.
    nums: [..]s32;

    // Fill the dynamic array with some values.
    loop i := 0; i < 100; i += 1 {
        // To append new value at the end of the array we can use 'array_push'
        // function.
        array_push(nums, i);

        // We can push only numbers of s32 type into the array (based on
        // declaration type), you can try to push something else and see what
        // happens.
    }

    // Dynamic arrays can be printed as usual...
    print("nums = %\n", nums);

    // We can use [N] operator to access single array elements like this:
    print("nums[10] = %\n", nums[10]);
    print("nums[20] = %\n", nums[20]);

    // Since dynamic array will allocate memory on heap, we must free this
    // memory by 'array_terminate' call when array is no longer needed.
    array_terminate(nums);

    // There is lot of other ways to modify dynamic array content, check out
    // API documentation.

    return 0;
}