# arena_pool.ludic - a pool that keeps its records across frames through a generic push (the shape of
# ludic.ui's nd_take and ui_kept). Built with --arena, a record the pool keeps must not come from the
# frame's scratch: run with R3D_ARENA_CHECK=1 (each reset filled with 0xDD) it prints what it prints
# with the arena off (R3D_ARENA=0) - `7 3498`.
program ArenaPool {
  property Cell { v: int = 0, tag: string = "" }
  property Pool { cells: []Cell = new []Cell, used: int = 0 }
  function kept<T>(xs: []T, v: T) -> void { push(xs, v) }
  function take(p: Pool, f: int) -> Cell {
    if p.used < len(p.cells) {
      let c = p.cells[p.used]
      p.used += 1
      return c
    }
    let c = new Cell { v: f }
    kept(p.cells, c)
    p.used += 1
    return c
  }
  function step(p: Pool, f: int) -> int {
    p.used = 0
    var s = 0
    for k in 0 .. (f % 8) {
      let c = take(p, f)
      c.v = f + k
      s += c.v
    }
    return s
  }
  entry {
    let p = new Pool
    for f in 0 .. 500 {
      step(p, f)
      Mem.frame()
    }
    var sum = 0
    for i in 0 .. len(p.cells) { sum += p.cells[i].v }
    print(`{len(p.cells)} {sum}`)
  }
}