Andy Chambers wrote:
Hi,
This was mentioned a while ago and is causing a problem now. When an
ajax request comes in, one of the things that gets updated is the
input value. For example...
old: <input name="term" value=""/>
...user types in "progv" and hits TAB
new: <input name="term" value="progv"/>
We want the model on the server to update itself to reflect this
change but we don't need to send it down to the browser because the
browser already knows. The problem this is causing (and this is
something we'll need to take a mental note of for the future) is that
the event binding for the input element is lost when that element is
replaced. That means any actions after the first don't trigger an
ajax request.
We could rebind the event on the new element but I think its better
not to send it in the first place.
I think this would apply to all UI elements so if that's the case, the
solution is probably to filter updates containing these elements the
same way that ascendant and redundant nodes get filtered in the code
below.
(let ((updt (loop for (h . xh) in (updates
self)
unless (loop for (h2 . nil) in
(updates self)
thereis (unless (eq
h h2)
(when
(fm-ascendant-p h2 h)
(trc nil
"suppressing redundant" h :seeing-ascendant h2 (id h2))
t)))
collect xh)))
I've pushed a new version out to the repo but haven't dealt with this
problem yet.
Another thing you might notice if you look at commented out code in
the example is that the radio button at the bottom seems a bit
verbose. Radiobuttons could probably do with a layer on top providing
a nicer way of creating them.
Here is what I did for the exported-only checkbox (untested):
(defmacro mk-checkbox (label attribute &key top-args label-args input-args)
`(mk-div (,@topargs)
(mk-label (,@label-args :for ,(symbol-name attribute))
,label)
(mk-input (,@input-args
:name ,(symbol-name attribute) :id ,(symbol-name attribute)
:-type "checkbox"
:checked (c? (,attribute (u^ page))) ; parameterize?
:value (c? (,attribute (u^ page)))))))
And then you can just do:
(mk-checkbox "Exported Only" exported-only-p
:top-args (:one 1 :two 2))
And to think they banned even a preprocessor from Java. :)
Notes:
0. I mentioned first the idea of having a 'watched-parameter' slot on
the checkbox. Above macrology lets me achieve even more succinctness
without complicating the checkbox implementation which stays as minimal
as possible. Who does not get macros?!!! :)
1. Observe that parameters for any node must be in their own list.
2. I added a common parent (an extra mk-div) but hopefully that is OK,
seemes right anyway. If not, I have a work-around in mind, but macros
only emit one form so it would take (probably) a "flatten" call ...
hmmm, I suspect I am being daft: do these things end up going thru a
the-kids form anyway, which would flatten any list so the outer mk-div
could just be (list...)? Probably.
3. Will the top always be a page? Perhaps that is another parameter.
4. I started with an initial-value parameter then realized that is being
set at the page level. Then I noticed both checked and value mirroring
that. What I believe I have done (check Celtk) is have an intial-value
slot whose observer sets the parameter of whatever node is being
controlled (here the page). Actions on the checkbox likewise set the
parameter of the controlled node. Then the checkbox value (as you have
it) watches the parameter, but we at least author the parameter
completely (including initialization) from the authoring of the
checkbox. But I can see it going the other way, with the checkbox being,
say, an optional interface to a page value that would possibly be
maintained/originate elsewhere. Anyway, I am still curious about the
checkbox/value redundancy.
kt
_______________________________________________
cells-devel site list
cells-devel@common-lisp.net
http://common-lisp.net/mailman/listinfo/cells-devel
