Hi Holger,
> im quite excited to see you implement XBL in your formsPlayer!
We're big fans of it...it's a great way to define functionality in a
modular, re-usable way. And XForms really lends itself to using XBL; not
just the custom controls, but things like defining the extension XPath
functions (XForms allows extension functions to be defined by the author,
but doesn't specify how.)
> aside from the binding mechanism, is your implementation
> compatible to mozilla ?
Pretty much. We don't have a few things like getter and setter, and we don't
always know when CSS properties have changed, although we've done as much as
we can within the limitations of IE. (For example, both the 'World Clocks'
and 'Contact Database' demos show how the same SVG widget can have its size
set dynamically by CSS.) And of course once you get into the script syntax,
things can be very different since IE's DOM is much less standard than
Gecko's. But even here we're constantly adding things to narrow the
differences. So, for example, you don't need to use the usual:
var x = new ActiveXObject(...);
Instead we have made our DOM 3 Implementation Registry library available
from the IE DOM, so that you can bootstrap that to get your object-creation
factories, and therefore write more portable script. We also support DOM 2
Events, which helps a great deal in terms of compatibility.
(formsPlayer 1 only uses XBL for 'speaking' messages, but formsPlayer 2 uses
XBL for everything.)
> (i like the idea of expressisng binding definitions with
> xpath !)
I do too, but I'm sure that ultimately there will be many binding
mechanisms--CSS selectors, resolvers like ours that use XPath, and so on. To
give you yet another selection mechanism, as an experiment we have also
implemented the following syntax in formsPlayer 2:
<xf:input xbl:bind="#ipwidget" ref="ip">
<xf:label>Enter an IP address:</xf:label>
</xf:input>
<xbl:xbl id="ipwidget">
...
</xbl:xbl>
There are some situations where inline bindings like this make sense
(although you can really imagine it getting misused and making a right
mess!).
> p.s.:that reminds me, i really have to look into xForms...
Great! I'm looking forward to people from the SVG-world producing some real
XForms/SVG demos--I know that you'll all do far better ones than we ever
could.
In particular I'm excited to see what you all make of our mapping framework,
that should be available in the next few days. We've made some improvements
to the mapping samples that are on the Wiki (showing how to navigate Google
Maps and Microsoft TerraServer maps, in XForms). The enhancements will allow
you to overlay *any* items onto any backdrop. So you could use SVG
icons--perhaps animated weather symbols--on top of Google Maps, next to the
restaurant you are about to go to. Each overlaid item is simply an xf:output
control, but by doing it this way, it means you automatically get things
like mouseover text (or more graphics) for free, via xf:hint.
(And most importantly, it also means that a system that does not support SVG
will still have data that it can either display or speak. This is something
that is often lost in the discussions about whether to use SVG+JavaScript or
XForms+XBL.)
XBL really comes into its own in this mapping demo, allowing us to keep
separate the backdrops and the items that are overlaid onto them, and in
particular, managing the relationship between data from one co-ordinate
system being overlaid onto a map that uses another. With XBL this
complicated set of relationships starts to become manageable, and flexible
enough that you can even use it for things like chess boards!
And of course, the opposite is also true: without XBL this whole thing would
be pretty much impossible. Of course you could produce a static application,
and pre-compile it using Java, C++ or C#, or whatever...But that's so
1990s...... ;)
Regards,
Mark
Mark Birbeck
CEO
x-port.net Ltd.
e: [EMAIL PROTECTED]
t: +44 (0) 20 7689 9232
w: http://www.formsPlayer.com/
b: http://internet-apps.blogspot.com/
Download our XForms processor from
http://www.formsPlayer.com/
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