Jonas Ekstedt wrote:
I think the reason for taglibs are that rendering an object is often more complicated than simply outputting a value. For example, suppose you want to render a calendar covering the current month. This is a typical component that would lend itself well as a tag class. The template writer would simply do:
<calendar:month current-date="${myDate}"/>
The tag might output something like this:
<month value="2"> <week value="12"> <day value="5" name="Monday"/> <day value="6" name="Tuesday" current="true"/> <day value="7" name="Wednesday"/> ... </week> ... </month>
Later transformations would transform it into a table or whatever. This type of calendar would be very hard to do for a template author without the help of a tag library.
I have completely no time these days so I was just waiting for the single post to say: Cannot agree more here :)
I cannot disagree more.
${myDate as month}will do the above without mentioning tags (and will be much more Dreamweaver-friendly).
The current discussion about taglibs have focused very much on esql and
whether SQL belongs in templates or not. I agree that SQL in templates
are a bad idea, but that is really beside the point in regards to the
virtues of taglibs.
Exactly. Everyone concentrated on ESQL as a taglib while this is the WORST example there is. ESQL does a lot of persistence logic and can have enormous side effects. Taglibs should have no side effects at all.
excuse me? what side effect does a SELECT have?
Taglibs (in my view) are primarily about converting
objects to SAX.
If this is the case, then "taglib" is a *VERY BAD* name. I agree that some objects might be "sax-ified" differently, depending on user needs, but the name "taglibs" makes the syntactic and the semantic concern overlap and annoys people (like me) that ended up hating dynamic XML tags after promoting them for so long.
Here are a few ideas for taglibs that only deals withpresentation of objects (as opposed to esql which also populates).
* Bean renderers
<jx:set var="ignored" value="${Packages.com.something.DateUtil.emitPrettyDate( bean.startDate, cocoon.consumer"/> - is this one better than the taglib? Or should I implement a stylesheet that would parse my 100kB xml file just to look for <dateutils:prettydate value="2003-01-01"/> ?
I completely agree that the transformation stage is overkill, that's not my point.
I think that better than both you can do
${bean.startDate as YYYY-MM-DD}* DOM renderers
excuse me?
* ResultSet renderers (ie renders a query made in flow)
are you kidding? regular iteration is all you need.
* Menus * Page navigation * Tabs (similar to tabs in CForm)
what?
* CForm tags
the above ${var as flavor} will do
* cinclude
no way
* Calendars (showing week, month etc.)
see above
* wiki renderers currently I do something like to parse wiki syntax:
function radeoxToSAX( str, consumer ) {
var radeoxStr = radeoxEngine.render( str, radeoxContext );
var buffer = new java.lang.StringBuffer("<root>" );
buffer.append( radeoxStr )
buffer.append( "</root>" );
var is = new Packages.org.xml.sax.InputSource( new java.io.StringReader( buffer.toString() ) );
var parser = null;
var includeConsumer = new org.apache.cocoon.xml.IncludeXMLConsumer( consumer, consumer );
includeConsumer.setIgnoreRootElement( true );
try { parser = cocoon.getComponent( Packages.org.apache.excalibur.xml.sax.SAXParser.ROLE );
parser.parse( is, includeConsumer ); } finally {
if ( parser != null ) cocoon.releaseComponent( parser );
}
}
<jx:macro name="radeox-string"> <jx:parameter name="value"/> <jx:set var="ignored" value="${cocoon.session.radeox( value, cocoon.consumer )}"/> </jx:macro>
OH COME ON! you can do a generator and cinclude a subpipeline for that.
<snip/>
<radeox-string value="${project.description}"/> This clearly is a hack and should be implemented as taglib.
You will have to step on my dead body before that's the case.
* ValueList renderers a taglib that supports displaying a narrowed list of values, searchable, paginable and so on
The items above are in my view better examples of the benefits of
taglibs. They're all about how to render an object. The object is
populated in flow but how to render it is implemented in the tag
classes.
Maybe we should stop using "taglib" word. What we're trying to do may simply be harmed by the emotions that this phrase carries.
No matter what you call it, if you want to have dynamic XML tags, you will hurt yourself, your wiki example is the kind of things that gives me the creeps.
-- Stefano.
