Mercurial > urweb

con colMeta = fn t_formT :: (Type * Type) => {
        Nam : string,
        Show : t_formT.1 -> xbody,
        Widget : nm :: Name -> xml form [] [nm = t_formT.2],
        WidgetPopulated : nm :: Name -> t_formT.1 -> xml form [] [nm = t_formT.2],
        Parse : t_formT.2 -> t_formT.1,
        Inject : sql_injectable t_formT.1
}
con colsMeta = fn cols :: {(Type * Type)} => $(Top.mapT2T colMeta cols)

fun default (t ::: Type) (sh : show t) (rd : read t) (inj : sql_injectable t)
            name : colMeta (t, string) =
    {Nam = name,
     Show = txt _,
     Widget = fn nm :: Name => (<xml><textbox{nm}/></xml>),
     WidgetPopulated = fn (nm :: Name) n =>
                          (<xml><textbox{nm} value={show _ n}/></xml>),
     Parse = readError _,e
     Inject = _}

val int = default _ _ _
val float = default _ _ _
val string = default _ _ _

fun bool name = {Nam = name,
                 Show = txt _,
                 Widget = fn nm :: Name => (<xml><checkbox{nm}/></xml>),
                 WidgetPopulated = fn (nm :: Name) b =>
                                      (<xml><checkbox{nm} checked={b}/></xml>),
                 Parse = fn x => x,
                 Inject = _}

functor Make(M : sig
        con cols :: {(Type * Type)}
        constraint [Id] ~ cols
        val tab : sql_table ([Id = int] ++ mapT2T fstTT cols)

        val title : string

        val cols : colsMeta cols
end) = struct

open constraints M
val tab = M.tab

sequence seq

fun create (inputs : $(mapT2T sndTT M.cols)) =
    id <- nextval seq;
    () <- dml (insert tab
                      (foldT2R2 [sndTT] [colMeta]
                                [fn cols => $(mapT2T (fn t :: (Type * Type) =>
                                                         sql_exp [] [] [] t.1) cols)]
                                (fn (nm :: Name) (t :: (Type * Type)) (rest :: {(Type * Type)})
                                                 [[nm] ~ rest] =>
                                 fn input col acc => acc with nm = sql_inject col.Inject (col.Parse input))
                                {} [M.cols] inputs M.cols
                       with #Id = (SQL {id})));
    return <xml><body>
      Inserted with ID {txt _ id}.
    </body></xml>

fun save (id : int) (inputs : $(mapT2T sndTT M.cols)) =
    () <- dml (update [mapT2T fstTT M.cols]
                      (foldT2R2 [sndTT] [colMeta]
                                [fn cols => $(mapT2T (fn t :: (Type * Type) =>
                                                         sql_exp [T = [Id = int] ++ mapT2T fstTT M.cols] [] [] t.1) cols)]
                                (fn (nm :: Name) (t :: (Type * Type)) (rest :: {(Type * Type)})
                                                 [[nm] ~ rest] =>
                                 fn input col acc => acc with nm = sql_inject col.Inject (col.Parse input))
                                {} [M.cols] inputs M.cols)
                      tab (WHERE T.Id = {id}));
    return <xml><body>
      Saved!
    </body></xml>

fun update (id : int) =
    fso <- oneOrNoRows (SELECT tab.{{mapT2T fstTT M.cols}} FROM tab WHERE tab.Id = {id});
    case fso : (Basis.option {Tab : $(mapT2T fstTT M.cols)}) of
        None => return <xml><body>Not found!</body></xml>
      | Some fs => return <xml><body><form>
          {foldT2R2 [fstTT] [colMeta] [fn cols :: {(Type * Type)} => xml form [] (mapT2T sndTT cols)]
                    (fn (nm :: Name) (t :: (Type * Type)) (rest :: {(Type * Type)})
                                     [[nm] ~ rest] (v : t.1) (col : colMeta t)
                                     (acc : xml form [] (mapT2T sndTT rest)) =>
                        <xml>
                          <li> {cdata col.Nam}: {col.WidgetPopulated [nm] v}</li>
                          {useMore acc}
                          </xml>)
                    <xml/>
                    [M.cols] fs.Tab M.cols}

                    <submit action={save id}/>
      </form></body></xml>

fun delete (id : int) =
    () <- dml (DELETE FROM tab WHERE Id = {id});
    return <xml><body>
      The deed is done.
    </body></xml>

fun confirm (id : int) = return <xml><body>
    <p>Are you sure you want to delete ID #{txt _ id}?</p>

    <p><a link={delete id}>I was born sure!</a></p>
</body></xml>

fun main () =
    rows <- queryX (SELECT * FROM tab AS T)
                   (fn (fs : {T : $([Id = int] ++ mapT2T fstTT M.cols)}) => <xml>
                       <tr>
                         <td>{txt _ fs.T.Id}</td>
                         {foldT2RX2 [fstTT] [colMeta] [tr]
                                    (fn (nm :: Name) (t :: (Type * Type)) (rest :: {(Type * Type)})
                                                     [[nm] ~ rest] v col => <xml>
                                                         <td>{col.Show v}</td>
                                                       </xml>)
                                    [M.cols] (fs.T -- #Id) M.cols}
                         <td><a link={update fs.T.Id}>[Update]</a> <a link={confirm fs.T.Id}>[Delete]</a></td>
                       </tr>
                     </xml>);
    return <xml><head>
      <title>{cdata M.title}</title>

    </head><body>

    <h1>{cdata M.title}</h1>

    <table border={1}>
      <tr>
        <th>ID</th>
        {foldT2RX [colMeta] [tr]
                  (fn (nm :: Name) (t :: (Type * Type)) (rest :: {(Type * Type)})
                                   [[nm] ~ rest] col => <xml>
                                       <th>{cdata col.Nam}</th>
                                     </xml>)
                  [M.cols] M.cols}
      </tr>
      {rows}
    </table>

    <br/>

    <form>
      {foldT2R [colMeta] [fn cols :: {(Type * Type)} => xml form [] (mapT2T sndTT cols)]
               (fn (nm :: Name) (t :: (Type * Type)) (rest :: {(Type * Type)})
                                [[nm] ~ rest] (col : colMeta t) (acc : xml form [] (mapT2T sndTT rest)) => <xml>
                                    <li> {cdata col.Nam}: {col.Widget [nm]}</li>
                                    {useMore acc}
                                  </xml>)
       <xml/>
           [M.cols] M.cols}

           <submit action={create}/>
    </form>
    </body></xml>

end
author	Adam Chlipala <adamc@hcoop.net>
date	Thu, 16 Oct 2008 14:17:55 -0400
parents	28d3d7210687
children	226c977faa9c