Mercurial > urweb
changeset 781:c884a42599f3
crud3 demo
| author | Adam Chlipala <adamc@hcoop.net> |
|---|---|
| date | Sun, 03 May 2009 16:00:43 -0400 |
| parents | 0084af7af35a |
| children | a44daa674810 |
| files | demo/crud3.ur demo/crud3.urp demo/prose |
| diffstat | 3 files changed, 38 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/demo/crud3.ur Sun May 03 16:00:43 2009 -0400 @@ -0,0 +1,27 @@ +table t : {Id : int, Text : string} + PRIMARY KEY Id + +open Crud.Make(struct + val tab = t + + val title = "Crud3" + + val cols = {Text = {Nam = "Text", + Show = txt, + Widget = (fn (nm :: Name) => <xml> + <subform{nm}> + <textbox{#A}/> + <textbox{#B}/> + </subform> + </xml>), + WidgetPopulated = (fn (nm :: Name) s => <xml> + <subform{nm}> + <textbox{#A} value={s}/> + <textbox{#B}/> + </subform> + </xml>), + Parse = (fn p => p.A ^ p.B), + Inject = _ + } + } + end)
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/demo/crud3.urp Sun May 03 16:00:43 2009 -0400 @@ -0,0 +1,5 @@ +database dbname=test +sql crud3.sql + +crud +crud3
--- a/demo/prose Sun May 03 15:53:29 2009 -0400 +++ b/demo/prose Sun May 03 16:00:43 2009 -0400 @@ -231,6 +231,12 @@ <p>This example shows another application of <tt>Crud.Make</tt>. We mix one standard column with one customized column. We write an underscore for the <tt>Inject</tt> field of meta-data, since the type class facility can infer that witness.</p> +crud3.urp + +<p>One thing that is unclear from the previous examples is how to provide more complex, multi-input widgets for taking input meant for particular fields. The signature of <tt>Crud.Make</tt> forces every widget to define exactly one input. The <tt><subform></tt> tag, the simpler cousin of the <tt><subforms></tt> tag that we saw earlier, provides a fix for this problem. Via <tt><subform></tt>, an arbitrary form can be turned into a single record-valued input.</p> + +<p>We use that possibility here to define a silly widget for a <tt>string</tt> column, which concatenates the values entered into two different textboxes.</p> + alert.urp <p>Ur/Web makes it easy to write code whose execution should be distributed between the web server and client web browsers. Server-side code is compiled to efficient native code, and client-side code is compiled to JavaScript. Ur/Web programmers don't need to worry about these details, because the language and standard library provide a uniform ML-like interface for the whole process.</p>