On Thu, 12 Dec 2002 goran.hultgren at bluefish.se wrote:

> I have my doubts. But the idea of going with the "programmatic" approach
> being able to add "tracking device ids and divs", then feeding the pages
> to the designer and back and producing some kind of internal template
> DOM-kindof thing and finally simply "turn off" the minimal visual fluff
> that was needed from the start feels like a real cool way of doing it.
> Sortof XMLC inspired but a bit more "round-trippy". :-)

I think generated tracking ids are going to be more trouble than they're
worth - if they're generated, all they can really reflect is sequence, and
that's not terribly stable.  So I think we should be going on
developer-provided ids, which means we might as well use the CSS id
attribute (and ensure that everything thus has a CSS id while we're at
it).

So what we're building is an HTML merge tool - you have to merge
the HTML generation code with the HTML template from the designer.
I've been thinking about how you would manage this with HtmlRenderer (or
HV's HtmlBuilder), but actually, I think it would be much, much easier to
do at the HTML level, when you have two complete pieces of output.  That
also means it could stand on its own, apart from either Seaside or HV.

So we narrow to this: you have two HTML documents, both with
matching CSS ids, one with content, and one with presentation fluff.  You
want to merge the content from one into the fluff of the other.

As a first pass, how about this: take the fluffed document.  Any element
that is found that matches an element (same id) in the content document,
has its attributes replaced with the equivalents from the content
document.  Elements whose only child is a piece of text, should have
that text treated as an attribute as well.  The tag names are always taken
from the fluff document.

Once an element has been matched, its children should be matched against
the children of the corresponding content element.

If a content element repeats, the corresponding template element should
also be repeated.

So, if your content output is this:

<h1>Edit Names</h1>

<form id="names" action="1245">
<div id="nameRow">
  <span class="label">1</td>
  <input type="text" name="1" id="name" value="Avi">
</div>

<div id="nameRow">
  <span class="label">2</span>
  <input type="text" name="2" id="name" value="Goran">
</div>

<input type="submit">
</form>

and your template is this:

<form id="names">
<table>
<tr>
 <td colspan="2">Edit Names</td>
</tr>
<tr id="nameRow">
 <td class="label" align="right">42</td>
 <td><input type="text" id="name" size="40"></td>
</tr>
<tr>
  <td colspan="2"><input type="submit" value="Save"></td>
</tr>
</table>

then the final output should be this:

<form id="names" action="12345">
<table>
<tr>
 <td colspan="2">Edit Names</td>
</tr>
<tr id="nameRow">
  <td class="label" align="right">1</td>
  <td><input type="text" id="name" size="40" name="1" value="Avi"></td>
</tr>
<tr id="nameRow">
  <td class="label" align="right">2</td>
  <td><input type="text" id="name" size="40" name="2" value="Goran"></td>
</tr>
<tr>
  <td colspan="2"><input type="submit" value="Save"></td>
</tr>
</table>

Now obviously those rules are somewhat open to interpretation, and we need
to write some solid test cases, but I don't think they're impossible to
implement, and they may be flexible enough to do what you want.

But then, it's late, so this may be gibberish.

The hardest part, incidentally, will be handling non-regular repeats.
What if every nth row has an image in it that the others don't?  How can
the template represent that?

> The only thing I can't really see is how to handle the "component"
> aspect. The webdesigner wants to work with pages (I guess) but a page
> may be composed of Seaside/HttpView components of some sort. What do we
> do with the glorified page when it comes back? How would the mapping be
> done?

Yes, it's awkward.  Put some comments marking the beginning and end of
each component, and split the template into those segments when you read
it in.  The comments will have info about which component class those
segments should be attached to.  The difficult part is that the same
components will show up in multiple templates, and how do you pick which
version to use?

Avi