On Thu, Jul 15, 2010 at 1:24 PM, Goswin von Brederlow <goswin-...@web.de>wrote:
> It is too bad I don't want to learn CML but use Ocaml. The CML examples
> from the book don't translate into ocaml since the interface is just a
> little bit different and those differences are what throws me off.
>
> So could you give a short example? E.g. the merge sort from the book.
>
You're right: OCaml's syntax differs enough from the text that it's annoying
to cut-n-paste the examples. Fortunately most example are a few lines of
code, so I didn't realize how difficult it could be on a larger example
(like the merge sort example.)
Attached is my translation of the mergeSort from the book. You get to play
with it and see if it works :)
--
Rich
Google Reader: https://www.google.com/reader/shared/rich.neswold
Jabber ID: r...@neswold.homeunix.net
open Event
let mySend c d = sync (send c d)
and myRecv c = sync (receive c)
let spawn f =
ignore (Thread.create f ())
let split (inCh, outCh1, outCh2) =
let rec loop = function
| (None, _, _) -> (mySend outCh1 None; mySend outCh2 None)
| (x, out1, out2) -> (mySend out1 x; loop (myRecv inCh, out2, out1))
in
loop (myRecv inCh, outCh1, outCh2)
let merge (inCh1, inCh2, (outCh : int option channel)) =
let rec copy (fromCh, toCh) =
let rec loop v =
begin
mySend toCh v;
match v with
| Some _ -> loop (myRecv fromCh)
| None -> ()
end
in
loop (myRecv fromCh)
and mergep (from1, from2) =
match (from1, from2) with
| (None, None) -> mySend outCh None
| (_, None) -> (mySend outCh from1; copy (inCh1, outCh))
| (None, _) -> (mySend outCh from2; copy (inCh2, outCh))
| (Some a, Some b) ->
if a < b then
(mySend outCh from1; mergep (myRecv inCh1, from2))
else
(mySend outCh from2; mergep (from1, myRecv inCh2))
in
mergep (myRecv inCh1, myRecv inCh2)
let rec mergeSort () =
let ch = new_channel() in
let sort () =
(match myRecv ch with
| None -> ()
| v1 ->
begin
(match myRecv ch with
| None -> mySend ch v1
| v2 ->
let ch1 = mergeSort()
and ch2 = mergeSort()
in
begin
mySend ch1 v1;
mySend ch2 v2;
split (ch, ch1, ch2);
merge (ch1, ch2, ch)
end);
mySend ch None
end)
in
(spawn sort; ch)
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