[Helma-dev] MarkupLib

[Hannes Wallnoefer]

I uploaded some initial code that hopefully will soon result in a Helma 
Markup Library:

http://adele.helma.org/download/helma/contrib/hannes/markuplib/

For a short description of what I'm planning to do:

http://gobble.helma.org/Brainstorming/markup+objects/

The advantage of this approach compared to using AntvilleLib Html.* or 
verbatim HTML forms in skins is that you get an object representation of 
your forms that lets you do value manipulation, validation and caching 
in a very smooth way. Here's a snipped of code that illustrates its 
features:

function getForm() {
    // create form structure
    var form = HtmlForm("form", {method: "post"}, [
        HtmlInput("name", {size: 40}),
        HtmlTextarea("body", {rows: 10, cols: 50}),
        HtmlInput("counter", {size: 5}),
        HtmlInput("save", {type: "submit", value: "go"})
    ]);

    // populate form from this
    form.populate(this);

    // set up validation hooks
    form.all.name.validate = function() {
        this.value = this.value.toUpperCase();
    }
    form.all.body.validate = function() {
        this.value = this.value.toLowerCase();
    }
    form.all.counter.validate = function() {
        var value = parseInt(this.value);
        this.value = isNaN(value) ? 0 : ++value;
    }

    return form;
}

function form_test_action() {
    var form = this.getForm();

    // if form submitted, read request and validate
    if (req.isPost()) {
        form.populate(req.data);
        form.validate();
    }

    // render form
    form.render();
}

One big missing part is skin interoperability. It's currently not 
possible to embed Markup objects in skins, i.e. there is no way to place 
markup elements within a skin using macros. There's no trivial way of 
doing this (short of setting up macros or macro properties dynamically), 
which led me to the conclusion that the Helma macro lookup code is too 
rigid. I'm currently considering adding macro resolutino via a 
renderMacro(name) function. Let me know if you have any ideas/opinions 
on this.

BTW, I think this might be destined to become part of HelmaLib. 
Currently, everything is implemented as HopObjects, but we don't really 
use any HopObject features, so it might as well be implemented as 
vanilla JS objects in Global.

Hannes