[OpenAjaxIDE] Multiselect properties - must have datatype of array

Wayne Vicknair waynev at us.ibm.com
Thu Aug 7 07:56:35 PDT 2008

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.

(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                                               
             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>                  
             08/06/08 07:50 PM         Re: [OpenAjaxIDE] Multiselect       
                                       properties - must have datatype of  

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

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

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
____<option value="tiger"><label
____<option value="cat"><label locid="animal_cat">House
____<option value="dog"><label locid="animal_dog">Man's best

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

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 _______________________________________________
IDE mailing list
IDE at openajax.org

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