changeset 406:a71600cac815

Form example
author Adam Chlipala <adamc@hcoop.net>
date Tue, 21 Oct 2008 17:30:06 -0400
parents 948315ea84c3
children 345fcf91c806
files demo/form.ur demo/form.urp demo/form.urs demo/listShop.urp demo/prose lib/basis.urs
diffstat 6 files changed, 37 insertions(+), 7 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/form.ur	Tue Oct 21 17:30:06 2008 -0400
@@ -0,0 +1,18 @@
+fun handler r = return <xml><body>
+  <table>
+    <tr> <th>A:</th> <td>{[r.A]}</td> </tr>
+    <tr> <th>B:</th> <td>{[r.B]}</td> </tr>
+    <tr> <th>C:</th> <td>{[r.C]}</td> </tr>
+  </table>
+</body></xml>
+
+fun main () = return <xml><body>
+  <form>
+    <table>
+      <tr> <th>A:</th> <td><textbox{#A}/></td> </tr>
+      <tr> <th>B:</th> <td><textbox{#B}/></td> </tr>
+      <tr> <th>C:</th> <td><checkbox{#C}/></td> </tr>
+      <tr> <th/> <td><submit action={handler}/></td> </tr>
+    </table>
+  </form>
+</body></xml>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/form.urp	Tue Oct 21 17:30:06 2008 -0400
@@ -0,0 +1,2 @@
+
+form
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/demo/form.urs	Tue Oct 21 17:30:06 2008 -0400
@@ -0,0 +1,1 @@
+val main : unit -> transaction page
--- a/demo/listShop.urp	Tue Oct 21 17:12:22 2008 -0400
+++ b/demo/listShop.urp	Tue Oct 21 17:30:06 2008 -0400
@@ -1,4 +1,3 @@
-debug
 
 list
 listFun
--- a/demo/prose	Tue Oct 21 17:12:22 2008 -0400
+++ b/demo/prose	Tue Oct 21 17:30:06 2008 -0400
@@ -36,7 +36,13 @@
 
 link.urp
 
-<p>This is my second favorite.</p>
+<p>In <tt>link.ur</tt>, we see how easy it is to link to another page.  The Ur/Web compiler guarantees that all links are valid.  We just write some Ur/Web code inside an "antiquote" in our XML, denoting a transaction that will produce the new page if the link is clicked.</p>
+
+form.urp
+
+<p>Here we see a basic form.  The type system tracks which form inputs we include, and it enforces that the form handler function expects a record containing exactly those fields, with exactly the proper types.</p>
+
+<p>In the implementation of <tt>handler</tt>, we see the notation <tt>{[...]}</tt>, which uses type classes to inject values of different types (<tt>string</tt> and <tt>bool</tt> in this case) into XML.  It's probably worth stating explicitly that XML fragments <i>are not strings</i>, so that the type-checker will enforce that our final piece of XML is valid.</p>
 
 listShop.urp
 
--- a/lib/basis.urs	Tue Oct 21 17:12:22 2008 -0400
+++ b/lib/basis.urs	Tue Oct 21 17:30:06 2008 -0400
@@ -366,15 +366,19 @@
 val submit : ctx ::: {Unit} ->  use ::: {Type}
              -> fn [[Form] ~ ctx] =>
                    unit
-                   -> tag [Action = $use -> transaction page]
+                   -> tag [Value = string, Action = $use -> transaction page]
                           ([Form] ++ ctx) ([Form] ++ ctx) use []
 
 (*** Tables *)
 
-val tabl : unit -> tag [Border = int] [Body] [Body, Table] [] []
-val tr : unit -> tag [] [Body, Table] [Body, Tr] [] []
-val th : unit -> tag [] [Body, Tr] [Body] [] []
-val td : unit -> tag [] [Body, Tr] [Body] [] []
+val tabl : other ::: {Unit} -> fn [other ~ [Body, Table]] =>
+                                  unit -> tag [Border = int] ([Body] ++ other) ([Body, Table] ++ other) [] []
+val tr : other ::: {Unit} -> fn [other ~ [Body, Table, Tr]] =>
+                                unit -> tag [] ([Body, Table] ++ other) ([Body, Tr] ++ other) [] []
+val th : other ::: {Unit} -> fn [other ~ [Body, Tr]] =>
+                                unit -> tag [] ([Body, Tr] ++ other) ([Body] ++ other) [] []
+val td : other ::: {Unit} -> fn [other ~ [Body, Tr]] =>
+                                unit -> tag [] ([Body, Tr] ++ other) ([Body] ++ other) [] []
 
 
 (** Aborting *)