(* The Zelus compiler, version 2024-dev
  (2025-06-4-15:49) *)
open Ztypes

type ('e, 'd, 'c, 'b, 'a) ball =
  { mutable time: 'e; mutable major: 'd; mutable up: 'c;
    mutable y': 'b; mutable y: 'a }

let ball =
  let machine cstate = 
    let alloc _ =
      cstate.cmax <- cstate.cmax + 1;
      cstate.zmax <- cstate.zmax + 1;
      { time = -1.;
        major = false;
        up = { zin = false; zout = 1. };
        y' = -1.;
        y = { pos = -1.; der = 0. };
      } in
    let step self _ =
      let cindex = cstate.cindex in
      let cpos = ref cindex in
      let zindex = cstate.zindex in
      let zpos = ref zindex in
      cstate.cindex <- cstate.cindex + 1;
      cstate.zindex <- cstate.zindex + 1;
      self.major <- cstate.major;
      self.time <- cstate.time;
      if cstate.major then
        for i = cindex to 0 do Zls.set cstate.dvec i 0. done
      else begin
        self.y.pos <- Zls.get cstate.cvec !cpos;
        cpos := !cpos + 1
      end;
      let result =
        self.up.zout <- -. self.y.pos;
        if self.up.zin then self.y' <- -0.8 *. self.y';
        self.y.der <- self.y';
        self.y.pos, self.y', self.up.zin in
      cpos := cindex;
      if cstate.major then begin
         Zls.set cstate.cvec !cpos self.y.pos;
         cpos := !cpos + 1;
         self.up.zin <- false
      end else begin
        self.up.zin <- Zls.get_zin cstate.zinvec !zpos;
        zpos := !zpos + 1
      end;
      zpos := zindex;
      Zls.set cstate.zoutvec !zpos self.up.zout;
      zpos := !zpos + 1;
      Zls.set cstate.dvec !cpos self.y.der;
      cpos := !cpos + 1;
      result in
    let reset self =
      self.y.pos <- 50.; self.y' <- 0. in
    Node { alloc; step; reset } in
  machine