Mercurial > urweb
view demo/broadcast.ur @ 724:12ec14a6be0b
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author | Adam Chlipala <adamc@hcoop.net> |
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date | Thu, 16 Apr 2009 12:00:44 -0400 |
parents | 0406e9cccb72 |
children |
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functor Make(M : sig type t end) = struct sequence s table t : {Id : int, Client : client, Channel : channel M.t} PRIMARY KEY (Id, Client) type topic = int val inj : sql_injectable topic = _ val create = nextval s fun subscribe id = cli <- self; ro <- oneOrNoRows (SELECT t.Channel FROM t WHERE t.Id = {[id]} AND t.Client = {[cli]}); case ro of None => ch <- channel; dml (INSERT INTO t (Id, Client, Channel) VALUES ({[id]}, {[cli]}, {[ch]})); return ch | Some r => return r.T.Channel fun send id msg = queryI (SELECT t.Channel FROM t WHERE t.Id = {[id]}) (fn r => Basis.send r.T.Channel msg) fun subscribers id = r <- oneRow (SELECT COUNT( * ) AS N FROM t WHERE t.Id = {[id]}); return r.N end