(* 

%use "Distributions/implode_type.fsh" ;;

*)

(* implode_type : [[a]] -> [a] 

removes the (outermost) type boundary in an array of arrays. 

*)

let reverse_shape =
  folddim zerodim snocdim 
;;

let implode_type_sh xsh = 
  extendShape2 xsh (zeroShape xsh) 
;;

let implode_type_pr (y:var b) (x:var a) = 
  
primrec g (fun y -> fun (x:var a) -> y:= get x) (numdim #x) y x
where 
g n h (y: var b) (x:var a) = for 0 <= i < lendim #x do 
		h sub(y,i) sub(x,i) done
;;

let implode_type = 
  proc2fun implode_type_pr implode_type_sh
;;


let explode_type_sh k xsh = 
  primrec f (zerodim xsh) k 
  where 
    f n x = extendShape2 
	    x
	    (succdim  (lendim (zeroShape x)) 
	    (zerodim (preddim (zeroShape x))))
;;


let explode_type_pr y x = 
  let pr ndx yi = 
    yi := multi_sub ndx x
  in 
  idoall pr y 
;;

let explode_type k = 
  proc2fun explode_type_pr (explode_type_sh k) ;;