Well, ZPT is pretty slow moving these days, but there's a feature that I'd be interested in. It's inspired by Kid (http://lesscode.org/projects/kid/), which is very similar to ZPT. In it, you can have Python code:


But unlike PHP, ASP, and family, the Python code can't produce output and must be self-contained. This allows for a nice continuum as code becomes more complex; you can start out with a normal tal expression, move to a python: tal expression, and then move things into a header, and finally move things out into an external script.

For example, imagine a select box:

<select name="state">
 <option tal:repeat="state options/states"
  tal:attributes="href state/code;
    selected python: test(state['code'] == request.get('state',
        options.get('state'), 'selected')">
   <span tal:replace="state/code"/>
   <span tal:condition="state/long_name">:
    <span tal:replace="state/long_name"/></span>

Brutal, eh?  But we've probably all been there.  With a PI:

state_sel = []
for state in options['states']:
    state_data = {}
    if state['code'] == request.get('state', options.get('state')):
        state_data['selected'] = 'selected'
    state_data['description'] = state_data['code'] = state['code']
    if state['long_name']:
        state_data['description'] += ': ' + state['long_name']
<select name="state">
 <option tal:repeat="state state_sel"
  tal:attributes="value state/code selected state/selected | nothing"

It's not any shorter, but it sure is easier to write, and keeps the markup fairly clean.

Of course, in most environments there's ways to move this code elsewhere -- into an external function or into the code that calls this template. But that turns what's actually a very localized bit of display-related code into something else. This doesn't actually *belong* in the "controller"; the Python code is clearly part of the view. But it's also horribly ugly when put into the markup.

I think it's actually really good for ZPT's ideal of being friendly to people with different roles -- the markup becomes simple enough for someone who knows only HTML, and for those middling people (of which I think there are many) who would be comfortable with Python but aren't necessarily comfortable with adding code to a controller or a Python script (code which probably has much different duties), it gives them an easy transitional area.

Anyway, I think it's a nice idea, and would fit well into ZPT.

(I'd also love if ZPT did ${expr} substitution like Kid, but that's a different issue)

Ian Bicking  /  [EMAIL PROTECTED]  /  http://blog.ianbicking.org
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