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[hcoop/smlsql.git] / sql_client.sml
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1(*
2 * SQL database interfaces for Standard ML
3 * Copyright (C) 2003 Adam Chlipala
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *)
19
20(* Functor for creating a client from a minimal driver *)
21
22functor SqlClient(Driver : SQL_DRIVER) :> SQL_CLIENT
23 where type conn = Driver.conn =
24struct
25 open Driver
26
27 fun oneOrNoRows conn query =
28 fold conn (fn (row, NONE) => SOME row
29 | (_, SOME _) => raise Sql "Expected one or zero rows; got multiple") NONE query
30
31 fun oneRow conn query =
32 (case oneOrNoRows conn query of
33 NONE => raise Sql "Expected one row; got none"
34 | SOME row => row)
35
36 fun app conn f q = fold conn (fn (row, ()) => f row) () q
37 fun map conn f q = List.rev (fold conn (fn (row, out) => (f row)::out) [] q)
38
39 fun query conn q = List.rev (fold conn op:: [] q)
40end
41