HOW DO I JOIN THE FLEX.NET ALPHA/BETA TEST
GROUP????????? J
From: flexcoders@yahoogroups.com [mailto:flexcoders@yahoogroups.com] On Behalf Of Scott Barnes
Sent: Wednesday, May 18, 2005 5:13
AM
To: flexcoders@yahoogroups.com
Subject: Re: [flexcoders] E4X in
Flex 2.0, part 1: Reading XML
heheheheheheh thats funny.
I had to do a double take and thought "am i
reading the right list here or..."
Nice work ;)
On 5/18/05, Hans Omli <[EMAIL PROTECTED]>
wrote:
>
> I don't suppose we'll be reading part 2 of
this email via FlexCoders then.
> ;-)
>
> ________________________________
> From: flexcoders@yahoogroups.com
[mailto:flexcoders@yahoogroups.com]
On
> Behalf Of Gordon Smith
> Sent: Tuesday, May 17, 2005 5:15 PM
> To: 'flexcoders@yahoogroups.com'
> Subject: RE: [flexcoders] E4X in Flex 2.0,
part 1: Reading XML
>
>
>
> Oops... I meant to send this to an internal
group, not to flexcoders. Enjoy
> the information, but, for now, don't expect
this level of detail about our
> future plans. Of course, we do want your
feedback on features for the next
> release, and we'll be sharing more plans with
you in the future, as we get
> closer to the next release.
>
> Sorry,
> Gordon
>
>
> -----Original Message-----
> From: flexcoders@yahoogroups.com
[mailto:flexcoders@yahoogroups.com]
On
> Behalf Of Gordon Smith
> Sent: Tuesday, May 17, 2005 4:54 PM
> To: 'flexcoders@yahoogroups.com'
> Subject: [flexcoders] E4X in Flex 2.0, part
1: Reading XML
>
>
>
>
>
> As you may have gathered, we've been spending
a lot of time lately
> leveraging the new features of the Flash
Player in the new Flex application
> model. Naturally, you'll also be able to
leverage those same new features,
> so we thought we'd start giving you a run
down of what's new. Of course we
> don't have beta software for you to play with
yet, so for now, we'll provide
> a lot of detail so you can evaluate these new
features and give guidance for
> us.
>
>
>
> XML manipulation in Flex 2.0 is going to get
a lot more powerful, as well as
> faster. By the time that Flex 2.0 ships, the
Flash Player will support E4X
> ("ECMAScript for XML"), a set of
programming language extensions adding
> native XML support to ECMAScript. The player
team is busy implementing
> Standard ECMA-357 as described in
> http://www.ecma-international.org/publications/standards/Ecma-357.htm.
>
>
>
>
>
> Here's how the spec describes what this
feature offers: "E4X adds native XML
> datatypes to the ECMAScript language, extends
the semantics of familiar
> ECMAScript operators for manipulating XML
objects and adds a small set of
> new operators for common XML operations, such
as searching and filtering. It
> also adds support for XML literals,
namespaces, qualified names and other
> mechanisms to facilitate XML
processing."
>
>
>
>
>
> Lets take a look at a few examples of how you
can read XML data using E4X.
>
>
>
>
>
> As in the current player, you'll be able to
create variables of type XML by
> parsing a String. But XML literals will now
be supported as well:
>
>
>
>
>
> var employees:XML =
>
<employees>
>
<employee ssn="123-123-1234">
>
<name first="John" last="Doe"/>
>
<address>
>
<street>11 Main St.</street>
>
<city>San Francisco</city>
>
<state>CA</state>
>
<zip>98765</zip>
>
</address>
>
</employee>
>
<employee ssn="789-789-7890">
>
<name first="Mary" last="Roe"/>
>
<address>
>
<street>99 Broad St.</street>
>
<city>Newton</city>
>
<state>MA</state>
>
<zip>01234</zip>
>
</address>
>
</employee>
>
</employees>;
>
>
>
>
>
> Instead of using DOM-style APIs like
firstChild, nextSibling, etc., with E4X
> you just "dot down" to grab the
node you want. Multiple nodes are indexable
> with [n], similar to the elements of an
Array:
>
>
>
>
>
> trace(employees.employee[0].address.zip);
>
>
> ---
>
>
> 98765
>
>
>
>
>
> To grab an attribute, you just use the .@
operator:
>
>
>
>
>
>
trace([EMAIL PROTECTED]);
> ---
>
>
>
> 789-789-7890
>
>
>
>
>
> If you don't pick out a particular node, you
get all of them, as an
> indexable list:
>
>
>
>
>
>
trace(employees.employee.name);
>
>
> ---
>
>
> <name
first="John" last="Doe"/>
>
>
> <name first="Mary"
last="Roe"/>
>
>
>
>
>
> (And note that nodes even toString()
themselves into formatted XML!)
>
>
>
>
>
>
> A handy double-dot operator lets you omit the
"path" down into the XML
> _expression_, so you could shorten the previous
three examples to
>
>
>
>
>
>
trace(employees..zip[0]);
>
>
>
>
trace([EMAIL PROTECTED]);
>
>
>
>
trace(employees..name);
>
>
>
>
> You can use a * wildcard to get a list of
multiple nodes or attributes with
> various names, and the resulting list is
indexable:
>
>
>
>
>
>
trace(employees.employee[0].address.*);
>
>
> ---
>
>
> <street>11 Main St.</street>
>
>
> <city>San Francisco</city>
>
>
>
<state>CA</state>
>
>
>
<zip>98765</zip>
>
>
>
trace([EMAIL PROTECTED]);
> ---
>
>
> Doe
>
>
>
>
>
> You don't have to hard-code the identifiers
for the nodes or attributes...
> they can themselves be variables:
>
>
>
>
>
>
>
> var whichNode:String
= "zip";
>
trace(employees.employee[0].address[whichNode]);
>
>
> ---
>
>
> 98765
>
>
>
>
>
>
> var
whichAttribute:String = "ssn";
>
trace([EMAIL PROTECTED]);
> ---
>
>
> 789-789-7890
>
>
>
>
>
> A new for-each loop lets you loop over
multiple nodes or attributes:
>
>
>
>
>
> for each (var ssn:XML
in [EMAIL PROTECTED])
>
>
> {
>
>
>
trace(ssn);
>
>
> }
>
>
> ---
>
>
> 123-123-1234
> 789-789-7890
>
>
>
>
>
> Most powerful of all, E4X supports
"predicate filtering" using the syntax
> .(condition), which lets you pick out nodes
or attributes that meet a
> condition you specify using a Boolean
_expression_. For example, you can pick
> out the employee with a particular social
security number like this, and get
> her state:
>
>
>
>
>
> var ssnToFind:String
= "789-789-7890";
>
trace(employees.employee.(@ssn == ssnToFind)..state);
> ---
>
>
> MA
>
>
>
>
>
> Instead of using a simple conditional
operator like ==, you can also write a
> complicated predicate filtering function to
pick out the data you need.
>
>
>
>
>
> By the way, although none of my examples use
XML namespaces, E4X has
> complete support for them.
>
>
>
>
>
> Compared with the current XML support in the
Flash Player, E4X allows you to
> write less code and execute it faster because
more processing can be done at
> the native speed of C++.
>
>
>
>
>
> Since E4X is so powerful, we're working to
make Flex 2.0 play nicely with
> it. Components like List, ComboBox, and
DataGrid will be able to accept E4X
> expressions like employees..name as a
dataProvider. The <mx:XML> tag will be
> able to declare an E4X-style XML object in
MXML. WebService and HTTPService
> will be able to deliver E4X-style XML objects
across the wire, and they'll
> use the speed of E4X to do their own work
(such as constructing and
> desconstrucing SOAP packets) faster.
>
>
>
>
>
> For backward compability, the new player will
continue to support the
> old-style XML and XMLNode objects, with the
one change that the old XML
> class will be renamed to XMLDocument. The
renaming is necessary because the
> E4X standard specifies that the new type be
called XML. So if you have XML
> code and you want to continue using, just use
XMLDocument instead. But we'll
> be encouraging everyone to migrate to E4X
because it is so much simpler,
> faster, and more expressive.
>
>
>
>
>
> Please let us know whether you'll find E4X
useful in your particular
> applications.
>
>
>
>
>
> - Gordon
>
>
>
>
>
>
>
>
>
>
>
> ________________________________
> Yahoo! Groups Links
>
>
> To visit your group on the web, go to:
> http://groups.yahoo.com/group/flexcoders/
>
> To unsubscribe from this group, send an email
to:
> [EMAIL PROTECTED]
>
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--
Regards,
Scott Barnes
http://www.mossyblog.com
http://www.flexcoder.com
(Coming Soon)
Yahoo! Groups Links
