I just uploaded the latest T5 snapshots. I did some work on the template parser; you now have an alternate template syntax, more like Tapestry 4:
<span t:id="foo" t:type="Bar" param="literal-string"/>
In Tapestry 4, it would be the same, except
I'm struggling with what's the correct binding prefix? With <t:comp> the default binding prefix is "prop:", meaning a property name or property path unless an explicit prefix is given.
With invisibly instrumented elements, the expectation is that more of the parameters will be fixed string literals, so the default binding prefix is "literal:". Thus you might have to do the following:
<input type="text" t:id="userName" t:type="TextField" value="prop:userName" validate="validate:required"/>
However, there's some implemented and upcoming improvements that will shorten and simplify this snippet.
Notice that the t:id and value attributes are pretty much the same? That's a Dont Repeat Yourself violation; Tapestry 5 already handles this particular case: if the value parameter is omitted, it is assumed to match a property of the container with same name as the component's id. This is already implemented. So the example is reduced to:
<input type="text" t:id="userName" t:type="TextField" validate="validate:required"/>
The remaining ideas are not yet implemented.
<input type="text"> into the template for preview purposes. Tapestry should be able to deduce that we want a TextField component. That reduces the example to:
<input type="text" t:id="userName" validate="validate:required"/>
The final change refers to the validate parameter. It's type is FieldValidator, not string ... that's why we're invoking the "validate:" binding factory to convert the string ("required") into a FieldVaidator instance. I'm not sure what this would look like (either special code on the TextField component, or some additional logic to invoke the ValidateBindingFactory), but it seems to me we should be able to remove the "validate:" portion:
<input type="text" t:id="userName" validate="required"/>
This is part of the goal of Tapestry, that whether you're writing templates or Java code, you should only write the bare minimum that's necessary, and Tapestry should be able to fill in the gaps. That's partly convention over configuration, but the overall concept goes deeper than that.
This last bit, omitting the need for explicit binding prefixes, was a battle I lost in the Tapestry 4 time frame, but the approach I was taking then was more involved; a default binding prefix for each parameter. I just want Tapestry to realize that I supplied a simple string, but the component needs a FieldValidator, and that those come from athe ValidatorBindingFactory service. Tapestry should be able to close the loop on that without generating any surprises.