[OpenAjaxIDE] Multiselect properties - must have datatype of array

Jon Ferraiolo jferrai at us.ibm.com
Mon Aug 11 15:31:02 PDT 2008


After thinking about this one some more and doing some research, we need to
ask ourselves whether it makes sense to drop the 'multiple' attribute on
the <options> element. Yes, HTML's SELECT element allows multiple
selections, but none of the following systems offers the feature:
Dojo/Dijit, YUI, ExtJS, Spry, and the EnumValues feature in Google Gadgets,
Unless my research is wrong, it looks as if the lack of multi-select hasn't
harmed these other major UI systems. If we drop 'multiple' and someone
needs multi-select for a property, then among their alternatives would be
to find a clever way to use the other features (e.g., represent your
multi-select as a series of boolean properties) and/or create a custom
property editor.

Jon




                                                                           
             Wayne                                                         
             Vicknair/Austin/I                                             
             BM                                                         To 
                                       Bertrand Le Roy                     
             08/07/2008 12:16          <Bertrand.Le.Roy at microsoft.com>     
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                                                                   Subject 
                                       RE: [OpenAjaxIDE] Multiselect       
                                       properties - must have datatype of  
                                       array(Document link: Jon Ferraiolo) 
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           



OK. I get it. I think we need a new tag to describe "flags". The enums plus
bitwise operations are definitely a useful idiom to model. It seems like
we're trying to get too much out of <options> which was intended to model
HTML <select> behavior.

BTW, the values I described are already in metadata in our widget property
test cases.


Cheers,
Wayne
Wayne E. Vicknair
Consulting Product Design Professional
IBM SWG Emerging Internet Technologies
Office: 512.838.0707 Email: waynev at us.ibm.com



                                                                           
             Bertrand Le Roy                                               
             <Bertrand.Le.Roy@                                             
             microsoft.com>                                             To 
                                       Wayne Vicknair/Austin/IBM at IBMUS     
             08/07/08 01:21 PM                                          cc 
                                       "ide at openajax.org"                  
                                       <ide at openajax.org>,                 
                                       "ide-bounces at openajax.org"          
                                       <ide-bounces at openajax.org>, Jon     
                                       Ferraiolo/Menlo Park/IBM at IBMUS      
                                                                   Subject 
                                       RE: [OpenAjaxIDE] Multiselect       
                                       properties - must have datatype of  
                                       array                               
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




That's not the same thing. In both of the cases you describe, the valid
values are determined by the application developer, not by the framework
developer. The values for what you describe will *never* end up in the
metadata.

-----Original Message-----
From: Wayne Vicknair [mailto:waynev at us.ibm.com]
Sent: Thursday, August 07, 2008 7:57 AM
To: Bertrand Le Roy
Cc: ide at openajax.org; ide-bounces at openajax.org; Jon Ferraiolo
Subject: Re: [OpenAjaxIDE] Multiselect properties - must have datatype of
array

I believe that the <options> and <option> element combination do indeed
express a constrained, multiple-value parameter.  HTML DOM and Dojo's
dijit.form.MultiSelect both happen to implement that concept with an,
admittedly inefficient, array return value. That implementation does not
diminish the expressiveness of the <options> construct. An implementation
could choose to iterate over the array values converting them to numbers
and bitwise  or-ing them together.

Cheers,
(Embedded image moved to file: pic29320.gif)Wayne Wayne E. Vicknair
Consulting Product Design Professional IBM SWG Emerging Internet
Technologies
Office: 512.838.0707 Email: waynev at us.ibm.com




             Bertrand Le Roy
             <Bertrand.Le.Roy@
             microsoft.com>                                             To
             Sent by:                  Jon Ferraiolo/Menlo Park/IBM at IBMUS
             ide-bounces at opena                                          cc
             jax.org                   "ide at openajax.org"
                                       <ide at openajax.org>
                                                                   Subject
             08/06/08 07:50 PM         Re: [OpenAjaxIDE] Multiselect
                                       properties - must have datatype of
                                       array










Same thing that happens in C. Never been a problem as you rarely have the
many flag values. Storing a list of countries or states would be more
efficiently stored in more elaborate data structures. The use we have of
flags is typically stuff like read/write/readwrite or left, right, top,
bottom and combinations. You get the idea. Bit structures are way more
efficient for this type of situation.
Sure, HTML options are different but I’m not sure I see your point.
Anyway, that’s the design we have in our APIs and it would be nice if it
was possible to express it.

From: Jon Ferraiolo [mailto:jferrai at us.ibm.com]
Sent: Wednesday, August 06, 2008 5:32 PM
To: Bertrand Le Roy
Cc: ide at openajax.org
Subject: RE: [OpenAjaxIDE] Multiselect properties - must have datatype of
array



What happens if you are doing multi-select with more than (4bytes) 32
alternatives (e.g., # states in US) or more than (8bytes) 64 alternatives
(e.g., # countries in the world)?

HTML's OPTION element doesn't require the use of bit flags (i.e., values
which are powers of 2), and that's what our <option> element will be mapped
into for a large number of cases.


(Embedded image moved to file: pic32049.gif)Inactive hide details for
Bertrand Le Roy <Bertrand.Le.Roy at microsoft.com>Bertrand Le Roy
<Bertrand.Le.Roy at microsoft.com>


Options are for enums, right? If so, that is completely different from our
usage. Multiple value enums (or flags) have integer values (like in C) and
are combined through the | or operator. Testing for a specific value is
done with the & and operator.
So for example, you’d have:
<property name="FavoriteAnimals">
__<options multiple="true">
____<option value="1"><label locid="animal_panda">Panda</label></option>
____<option value="2"><label locid="animal_tiger">Tiger</label></option>
____<option value="4"><label locid="animal_cat">House cat</label></option>
____<option value="8"><label locid="animal_dog">Man's best
friend</label></option> __</options> </property>

And if the user picks Tiger and House Cat, that gives 6.

From: ide-bounces at openajax.org [mailto:ide-bounces at openajax.org] On Behalf
Of Jon Ferraiolo
Sent: Wednesday, August 06, 2008 10:14 AM
To: ide at openajax.org
Subject: [OpenAjaxIDE] Multiselect properties - must have datatype of array


Aaron Reed of IBM is implementing the <property><options multiple="true">
feature in the open source reference implementation and the question can up
about how to represent the multiple choices when the property value is
persisted into the property storage area. Here is an example:

<property name="FavoriteAnimals">
__<options multiple="true">
____<option value="panda"><label
locid="animal_panda">Panda</label></option>
____<option value="tiger"><label
locid="animal_tiger">Tiger</label></option>
____<option value="cat"><label locid="animal_cat">House
cat</label></option> ____<option value="dog"><label
locid="animal_dog">Man's best friend</label></option> __</options>
</property>

Let's suppose the user picked "Tiger" and "House cat".

Given that we are focused on JavaScript, our proposal is that the natural
way to store a multi-select option would be as a JavaScript array. In this
case, the array would be ["tiger","cat"].

Does this make sense to people?

If so, then should we change the spec to say that if a <property> uses
<options> with multiple="true", then the <property> element must have
datatype="[]".

A follow on question is whether we should require an array of Strings, or
is it OK to have an array of anything, such as Number? Is the array could
contain things other than String, then implementations would need to a
string-to-whatever conversion at some point (e.g., string-to-number). I
would thing that array-of-Strings is the way to go.

Jon _______________________________________________
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