Ur/Web: demo/refFun.ur annotate

Reactive record pattern

author	Adam Chlipala <adamc@hcoop.net>
date	Thu, 01 Jan 2009 11:04:09 -0500
parents	7ef4b2911b09
children	1a317a707d71

rev	line source
adamc@419	1 functor Make(M : sig
adamc@419	2 type data
adamc@419	3 val inj : sql_injectable data
adamc@419	4 end) = struct
adamc@419	5
adamc@419	6 type ref = int
adamc@419	7
adamc@419	8 sequence s
adamc@419	9 table t : { Id : int, Data : M.data }
adamc@419	10
adamc@419	11 fun new d =
adamc@419	12 id <- nextval s;
adamc@471	13 dml (INSERT INTO t (Id, Data) VALUES ({[id]}, {[d]}));
adamc@419	14 return id
adamc@419	15
adamc@419	16 fun read r =
adamc@471	17 o <- oneOrNoRows (SELECT t.Data FROM t WHERE t.Id = {[r]});
adamc@501	18 case o of
adamc@419	19 None => error <xml>You already deleted that ref!</xml>
adamc@501	20 \| Some r => return r.T.Data
adamc@419	21
adamc@419	22 fun write r d =
adamc@471	23 dml (UPDATE t SET Data = {[d]} WHERE Id = {[r]})
adamc@419	24
adamc@419	25 fun delete r =
adamc@471	26 dml (DELETE FROM t WHERE Id = {[r]})
adamc@420	27
adamc@419	28 end

Mercurial > urweb