[Petal] [IDEA] Hash with params

[Jean-Michel Hiver]

> It was a rather half-assed way of doing a specific thing that prefixes 
> nicely generalize.  With prefixes, the above can be written as 
> "/path/with/var:variable".

Gotcha! Brilliant idea. Now that I understand what it is about, I think
it'll be rather easy to implement with Petal. You'll be able to stack
prefixes too, which is a Petal feature suggested by William some time
ago.

It would be nice if this prefix business allowed parameters to be passed
to methods, functionality which I find very useful. I would really like
some kind of formal syntax allowing this kind of stuff in TALES. I guess
prefixes in paths is a nice step in the right direction!


Now some stuff about METAL. I'm still super-confused I am afraid :)

Am I right in seeing METAL as some kind of 'meta-template'?

As far as I can see, define-slot is only really some sort of
'tal:define_variable_with_current_xml_node' while fill-slot boils down
to a 'tal:replace_structure_unless_not_defined'.

define-macro serves as an indentifier. Which makes me think: Why not use
a more standard syntax for XML / HTML fragments in URLs when you do
includes? (i.e. use-macro="my/file.xml#mymacro").

and use-macro is just an include statement, except that it defines all
the fill-slot variables before doing the includes.

Have I got it right?


If / When this is implemented with Petal, the following macro should be
possible:

<ul tal:define="child self/root">
  <li metal:define-macro="sitemap_li">
    <a
      href="#"
      hreflang="en"
      lang="en"
      xml:lang="en"
      tal:attributes="href child/Full_Path;
                      hreflang child/Lang;
                      lang child/Lang;
                      xml:lang child/Lang"
      tal:content="child/Title"
    >Child Document Title</a>
    <ul
      petal:define="children child/Children"
      petal:condition="children"
      petal:repeat="child children"
    >
      <li metal:use-macro="#sitemap_li" />
    </ul>
  </li>
</ul>


Cheers,
Jean-Michel.