Draft proposal: Namespaces and CSS

We could consider it a B-feature to support the namespaces in scope for the Style tag case inside an MXML document, however, this information would have to be exposed to the Batik-based CSS Parser - which at this point in time is isolated from MXML.

On Friday 20 Feb 2009, Matt Chotin wrote:

> - Namespace qualification is now required for type selectors in CSS style

> declarations.



Couldn't the default be taken from the containing document (if using Style

tag), so it wouldn't be required in every single (most ?) blocks ?



> - When updating from Flex3, applications will either have to run in

> compatibility mode, or qualify their CSS type selectors using namespaces.



This seems sensible, perfect.



--

Tom Chiverton

Helping to synergistically administrate market-growth

****************************************************

Hey Sean,

The default @namespace should be possible at the style sheet level. I'm hoping that documentation will establish a convention, but the namespace is merely used at compile time to resolve a fully qualified ActionScript class name so your scenarios should work.

Any type selector will need to consider a namespace, but universal selectors (*, .foo, #myButton) are independent of namespace and thus won't need scoping.

I haven't heard from Flex Builder on auto-completion for @namespace styles yet, but they are aware of this proposal.

Pete

Is modifying the default namespace per file allowed or will it always be
the spark namespace?

Scenario 1.
Styles1.css
@namespace "http://ns.adobe.com/flex/spark";
Button { color: #990000; }
Styles2.css
@namespace "com.effectiveui.controls.*";
SearchButton { color: #990000; }

Scenario 2.
File com/effectiveui/controls/SearchButton.mxml

@namespace "com.effectiveui.controls.*";
SearchButton { color: #990000; }



Are these valid?

Are class selectors scoped to the default/custom namespace and then just
ignored by the style manager implementation, or are they always compiled
into the global space?
Do you expect Flex Builder 4 will provide autocompletion and namespace
insertion when defining type selectors in css files?

Sean Christmann


Matt Chotin wrote:
> A new discussion was started by Matt Chotin in
>
> Developers --
> Draft proposal: Namespaces and CSS
>
> Hey all,
>
> This is a draft proposal for how we'll update CSS support to handle
> disambiguating classes via namespace. Feedback appreciated here for now so
> when we get to the formal mini-spec we can rush it through.
>
> ---------
>
> Keeping in mind that most folks have indicated they don't use Type selectors
> much in CSS...
>
> - Namespace qualification is now required for type selectors in CSS style
> declarations.
> - Gumbo will use the CSS3 suggested syntax for declaring namespaces and
> prefixing type selectors. For the most common component namespace the
> default namespace can be used (ignore the actual namespace url value):
>
> > @namespace "http://ns.adobe.com/flex/spark";
> Button { color: #990000; }
>
>
> Otherwise, prefixes can be specified for each namespace:
>
> > @namespace "http://ns.adobe.com/flex/spark";
> @namespace cx "com.mycompany.*";
>
> Button { color: #990000; }
> cx|MyFancyButton { color: #000099; }
>
>
> - The namespace mappings that are currently used to map MXML tags to
> ActionScript class names will also apply to CSS3 type selectors. These
> mappings draw information from configured manifests in flex-config.xml,
> swcs' catalog.xml files, and local package namespaces (e.g. how in MXML you
> use xmlns:c="com.mycompany.*" to scope the package name for your custom
> component). Note that namespace/prefix mappings defined in MXML do not
> apply to the enclosing CSS.
>
> - Type selectors that are either not qualified by a namespace or do not
> resolve to an ActionScript class linked into the Application cause a warning
> at compile time.
>
> - The version compatibility flag forces the compiler to ignore type selector
> prefixes. This allows Flex 3 applications to continue to use type selectors
> without namespaces.
>
> - The runtime will only match against fully qualified class names going
> forward. When the compatibility version flag is set for Flex 3 or earlier,
> it only matches against local names.
>
> - When updating from Flex3, applications will either have to run in
> compatibility mode, or qualify their CSS type selectors using namespaces. We
> continue to discourage type selectors anywhere but the root application
> file, and a warning will be given if type selectors are used outside of the
> root application.
>
>
>
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