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|
datatype dlist'' t =
Nil
| Cons of t * source (dlist'' t)
datatype dlist' t =
Empty
| Nonempty of { Head : dlist'' t, Tail : source (source (dlist'' t)) }
con dlist t = source (dlist' t)
type position = transaction unit
fun headPos [t] (dl : dlist t) =
dl' <- get dl;
case dl' of
Nonempty { Head = Cons (_, tl), Tail = tl' } =>
cur <- get tl;
set dl (case cur of
Nil => Empty
| _ => Nonempty {Head = cur, Tail = tl'})
| _ => return ()
fun tailPos [t] (cur : source (dlist'' t)) new tail =
new' <- get new;
set cur new';
case new' of
Nil => set tail cur
| _ => return ()
val create [t] = source Empty
fun clear [t] (s : dlist t) = set s Empty
fun append [t] dl v =
dl' <- get dl;
case dl' of
Empty =>
tl <- source Nil;
tl' <- source tl;
set dl (Nonempty {Head = Cons (v, tl), Tail = tl'});
return (headPos dl)
| Nonempty {Tail = tl, ...} =>
cur <- get tl;
new <- source Nil;
set cur (Cons (v, new));
set tl new;
return (tailPos cur new tl)
fun replace [t] dl ls =
case ls of
[] => set dl Empty
| x :: ls =>
tl <- source Nil;
let
fun build ls acc =
case ls of
[] => return acc
| x :: ls =>
this <- source (Cons (x, acc));
build ls this
in
hd <- build (List.rev ls) tl;
tlS <- source tl;
set dl (Nonempty {Head = Cons (x, hd), Tail = tlS})
end
fun renderDyn [ctx] [ctx ~ body] [t] (f : t -> position -> xml (ctx ++ body) [] []) filter pos len dl = <xml>
<dyn signal={dl' <- signal dl;
case dl' of
Empty => return <xml/>
| Nonempty {Head = hd, Tail = tlTop} =>
let
fun render' prev dl'' len =
case len of
Some 0 => <xml/>
| _ =>
case dl'' of
Nil => <xml/>
| Cons (v, tl) =>
let
val pos = case prev of
None => headPos dl
| Some prev => tailPos prev tl tlTop
val len = Option.mp (fn n => n - 1) len
in
<xml><dyn signal={b <- filter v;
return (if b then
f v pos
else
<xml/>)}/>
<dyn signal={tl' <- signal tl;
return (render' (Some tl) tl' len)}/></xml>
end
fun skip pos hd =
case pos of
0 => return hd
| _ =>
case hd of
Nil => return hd
| Cons (_, tl) =>
tl' <- signal tl;
skip (pos-1) tl'
in
case pos of
None => return (render' None hd len)
| Some pos =>
hd <- skip pos hd;
return (render' None hd len)
end}/>
</xml>
fun renderFlat [ctx] [ctx ~ body] [t] (f : t -> position -> xml (ctx ++ body) [] []) filter =
let
fun renderFlat' len ls =
case len of
Some 0 => <xml/>
| _ =>
case ls of
[] => <xml/>
| p :: ls =>
let
val len =
case len of
None => None
| Some n => Some (n - 1)
in
<xml>{f p.1 p.2}{renderFlat' len ls}</xml>
end
in
renderFlat'
end
val split [t] =
let
fun split' acc (ls : list t) =
case ls of
[] => acc
| x1 :: [] => (x1 :: acc.1, acc.2)
| x1 :: x2 :: ls => split' (x1 :: acc.1, x2 :: acc.2) ls
in
split' ([], [])
end
fun merge [t] (cmp : t -> t -> signal bool) =
let
fun merge' acc (ls1 : list t) (ls2 : list t) =
case (ls1, ls2) of
([], _) => return (List.revAppend acc ls2)
| (_, []) => return (List.revAppend acc ls1)
| (x1 :: ls1', x2 :: ls2') =>
b <- cmp x1 x2;
if b then
merge' (x1 :: acc) ls1' ls2
else
merge' (x2 :: acc) ls1 ls2'
in
merge' []
end
fun sort [t] (cmp : t -> t -> signal bool) =
let
fun sort' (ls : list t) =
case ls of
[] => return ls
| _ :: [] => return ls
| _ =>
let
val (ls1, ls2) = split ls
in
ls1' <- sort' ls1;
ls2' <- sort' ls2;
merge cmp ls1' ls2'
end
in
sort'
end
fun render [ctx] [ctx ~ body] [t] f (r : {Filter : t -> signal bool,
Sort : signal (option (t -> t -> signal bool)),
StartPosition : signal (option int),
MaxLength : signal (option int)}) dl = <xml>
<dyn signal={len <- r.MaxLength;
cmp <- r.Sort;
pos <- r.StartPosition;
case cmp of
None => return (renderDyn f r.Filter pos len dl)
| Some cmp =>
dl' <- signal dl;
elems <- (case dl' of
Empty => return []
| Nonempty {Head = hd, Tail = tlTop} =>
let
fun listOut prev dl'' acc =
case dl'' of
Nil => return acc
| Cons (v, tl) =>
let
val pos = case prev of
None => headPos dl
| Some prev => tailPos prev tl tlTop
in
b <- r.Filter v;
tl' <- signal tl;
listOut (Some tl) tl' (if b then
(v, pos) :: acc
else
acc)
end
in
listOut None hd []
end);
elems <- sort (fn v1 v2 => cmp v1.1 v2.1) elems;
let
fun skip n ls =
case (n, ls) of
(0, _) => ls
| (n, _ :: ls) => skip (n-1) ls
| (_, []) => []
val elems =
case pos of
None => elems
| Some pos => skip pos elems
in
return (renderFlat f r.Filter len elems)
end}/>
</xml>
fun delete pos = pos
fun elements' [t] (dl'' : dlist'' t) =
case dl'' of
Nil => return []
| Cons (x, dl'') =>
dl'' <- signal dl'';
tl <- elements' dl'';
return (x :: tl)
fun elements [t] (dl : dlist t) =
dl' <- signal dl;
case dl' of
Empty => return []
| Nonempty {Head = hd, ...} => elements' hd
fun foldl [t] [acc] (f : t -> acc -> signal acc) =
let
fun foldl'' (i : acc) (dl : dlist'' t) : signal acc =
case dl of
Nil => return i
| Cons (v, dl') =>
dl' <- signal dl';
i' <- f v i;
foldl'' i' dl'
fun foldl' (i : acc) (dl : dlist t) : signal acc =
dl <- signal dl;
case dl of
Empty => return i
| Nonempty {Head = dl, ...} => foldl'' i dl
in
foldl'
end
|
