(* copyright 1998 YALE FLINT PROJECT *)
(* monnier@cs.yale.edu *)
signature OPT_UTILS =
sig
datatype ('a,'b) either = A of 'a | B of 'b
(* takes the fk of a function and returns the fk of the wrapper
* along with the new fk of the actual body *)
val fk_wrap : FLINT.fkind * FLINT.lty list option ->
(FLINT.fkind * FLINT.fkind)
(* this is a known APL function, but I don't know its real name *)
val filter : bool list * 'a list -> 'a list
(* A less brain-dead version of ListPair.all: returns false if
* length l1 <> length l2 *)
val ListPair_all : ('a * 'b -> bool) -> 'a list * 'b list -> bool
(* This is not a proper transposition in that the order is reversed
* in the following way: transpose x = map rev (proper_trans x) *)
exception Unbalanced
val transpose : 'a list list -> 'a list list
val foldl3 : ('a * 'b * 'c * 'd -> 'd) -> 'd -> 'a list * 'b list * 'c list -> 'd
end
structure OptUtils :> OPT_UTILS =
struct
local structure F = FLINT
structure LK = LtyKernel
in
datatype ('a,'b) either = A of 'a | B of 'b
fun bug msg = ErrorMsg.impossible ("OptUtils: "^msg)
fun fk_wrap ({inline,known,isrec,cconv},rtys') =
let val cconv' =
case cconv
of F.CC_FUN(LK.FF_VAR(f1,f2)) => F.CC_FUN(LK.FF_VAR(true, f2))
| (F.CC_FCT | F.CC_FUN(LK.FF_FIXED)) => cconv
val isrec' = Option.map (fn ltys => (ltys, F.LK_UNKNOWN)) rtys'
in ({isrec=isrec, known=known, cconv=cconv, inline=F.IH_ALWAYS},
{isrec=isrec', known=true, cconv=cconv', inline=inline})
end
fun filter ([],[]) = []
| filter (true::fs,x::xs) = x::(filter(fs, xs))
| filter (false::fs,x::xs) = (filter(fs, xs))
| filter _ = bug "unmatched list length in filter"
fun ListPair_all pred =
let fun allp (a::r1, b::r2) = pred(a, b) andalso allp (r1, r2)
| allp ([],[]) = true
| allp _ = false
in allp
end
exception Unbalanced
fun transpose [] = []
| transpose (xs::xss) =
let fun tr [] accs = accs
| tr (xs::xss) accs =
let fun f [] [] = []
| f (x::xs) (acc::accs) = (x::acc)::(f xs accs)
| f _ _ = raise Unbalanced
in tr xss (f xs accs)
end
in tr xss (map (fn x => [x]) xs)
end
fun foldl3 f =
let fun l s ([],[],[]) = s
| l s (x1::x1s,x2::x2s,x3::x3s) = l (f(x1,x2,x3,s)) (x1s,x2s,x3s)
| l _ _ = raise Unbalanced
in l
end
end
end