// Simple arena allocator
struct ArenaChunk {
mut:
    next ?&ArenaChunk
    used int
    cap  int
    data byteptr
}

struct Arena {
mut:
    head ?&ArenaChunk
}

fn arena_init(mut arena Arena, first_capacity int) {
    chunk := &ArenaChunk{
        next: 0
        used: 0
        cap:  first_capacity
        data: unsafe { malloc(first_capacity) }
    }
    arena.head = chunk
}

fn test_main() {
    mut green_arena := Arena{}
    arena_init(mut green_arena, 64 * 1024)
}