Ur/Web: demo/treeFun.ur annotate

RPC returning an option

author	Adam Chlipala <adamc@hcoop.net>
date	Sun, 08 Mar 2009 13:41:55 -0400
parents	20fab0e96217
children	1fb318c17546

rev	line source
adamc@469	1 functor Make(M : sig
adamc@469	2 type key
adamc@469	3 con id :: Name
adamc@469	4 con parent :: Name
adamc@469	5 con cols :: {Type}
adamc@469	6 constraint [id] ~ [parent]
adamc@469	7 constraint [id, parent] ~ cols
adamc@469	8
adamc@469	9 val key_inj : sql_injectable key
adamc@469	10 val option_key_inj : sql_injectable (option key)
adamc@469	11
adamc@469	12 table tab : [id = key, parent = option key] ++ cols
adamc@469	13 end) = struct
adamc@469	14
adamc@469	15 open M
adamc@469	16
adamc@469	17 fun tree (f : $([id = key, parent = option key] ++ cols) -> xbody)
adamc@469	18 (root : option M.key) =
adamc@469	19 let
adamc@469	20 fun recurse (root : option key) =
adamc@471	21 queryX' (SELECT * FROM tab WHERE {eqNullable' (SQL tab.{parent}) root})
adamc@469	22 (fn r =>
adamc@469	23 children <- recurse (Some r.Tab.id);
adamc@469	24 return <xml>
adamc@469	25 <li> {f r.Tab}</li>
adamc@469	26
adamc@469	27 <ul>
adamc@469	28 {children}
adamc@469	29 </ul>
adamc@469	30 </xml>)
adamc@469	31 in
adamc@469	32 recurse root
adamc@469	33 end
adamc@469	34
adamc@469	35 end

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