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About to begin optimization of recursive transaction functions
author Adam Chlipala <adamc@hcoop.net>
date Thu, 06 Nov 2008 17:09:53 -0500
parents
children 7cb418e9714f
comparison
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468:4efab85405be 469:b393c2fc80f8
1 functor Make(M : sig
2 type key
3 con id :: Name
4 con parent :: Name
5 con cols :: {Type}
6 constraint [id] ~ [parent]
7 constraint [id, parent] ~ cols
8
9 val key_inj : sql_injectable key
10 val option_key_inj : sql_injectable (option key)
11
12 table tab : [id = key, parent = option key] ++ cols
13 end) = struct
14
15 open M
16
17 fun tree (f : $([id = key, parent = option key] ++ cols) -> xbody)
18 (root : option M.key) =
19 let
20 fun recurse (root : option key) =
21 queryX' (SELECT * FROM tab WHERE tab.{parent} = {root})
22 (fn r =>
23 children <- recurse (Some r.Tab.id);
24 return <xml>
25 <li> {f r.Tab}</li>
26
27 <ul>
28 {children}
29 </ul>
30 </xml>)
31 in
32 recurse root
33 end
34
35 end