Here is an equivalent code of the Sql demo
(http://impredicative.com/ur/demo/sql.html) example, but with indented
xml style. It compiles!.
Adding an optional type annotation on "row", in case of typo errors,
makes the error message shorter and nicer.
(* ------------ *)
table t : { A : int, B : float, C : string, D : bool }
PRIMARY KEY A
type t_qry_item = {T: { A : int, B : float, C : string, D : bool }}
fun do_list () =
rows <- queryL (SELECT * FROM t) ;
return <ixml>
<table>
<tr> <th>A</th> <th>B</th> <th>C</th> <th>D</th>
$foldrmapx {rows} <| {row : t_qry_item}
<tr>
<td>{[row.T.A]}
<td>{[row.T.B]}
<td>{[row.T.C]}
<td>{[row.T.D]}
<td><form><submit action={delete row.T.A}
value="Delete"/></form>
<br/><hr/><br/>
<form>
<table>
<tr> <th>A:</th> <td><textbox{#A}/></td>
<tr> <th>B:</th> <td><textbox{#B}/></td>
<tr> <th>C:</th> <td><textbox{#C}/></td>
<tr> <th>D:</th> <td><checkbox{#D}/></td>
<tr> <th/> <td><submit action={add} value="Add Row"/></td>
</ixml>
and add r =
dml (INSERT INTO t (A, B, C, D)
VALUES ({[readError r.A]}, {[readError r.B]}, {[r.C]}, {[r.D]}));
xml <- do_list ();
return <ixml>
<body>
<p>Row added.
{xml}
</ixml>
and delete a () =
dml (DELETE FROM t
WHERE t.A = {[a]});
xml <- do_list ();
return <ixml>
<body>
<p>Row deleted
{xml}
</ixml>
fun main () =
xml <- do_list ();
return <ixml>
<body>
{xml}
</ixml>
(* ------------------- *)
Since queryL gives a result list with first element at the list bottom,
I have setup a foldright version and a foldleft one (versions of
List.mapX with tail recursion) by simply swapping the order of the xml
combination.
fun ixml_foldlmapx [a] [ctx ::: {Unit}] (f: a -> xml ctx [] []) (li:
list a): xml ctx [] [] =
let foldlmapx' li <xml/>
where fun foldlmapx' (li': list a) (acc: xml ctx [] []) =
case li' of
| x :: rest => foldlmapx' rest <xml>{acc}{f x}</xml>
| _ => acc
end
fun ixml_foldrmapx [a] [ctx ::: {Unit}] (f: a -> xml ctx [] []) (li:
list a): xml ctx [] [] =
let foldrmapx' li <xml/>
where fun foldrmapx' (li': list a) (acc: xml ctx [] []) =
case li' of
| x :: rest => foldrmapx' rest <xml>{f x}{acc}</xml>
| _ => acc
end
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