[Grok-dev] Re: Skinning/themeing
Martin Aspeli
optilude at gmx.net
Sat May 19 17:11:03 EDT 2007
Hi Martijn,
> It also supports evolution of the framework over time. I.e. you can
> introduce a new templating language evolutionarily and you're not locked
> into the same template language forever.
Definitely. Maybe it's not so much about being template neutral, as it
is about making a strong choice of one templating language and sticking
to it (at least until a compelling reason can be found to migrate
*everything* over to a new one).
>> but as a user of a framework,
>> I want the framework authors to have chosen the template solution for
>> me. And I want all documentation and code examples to use the same
>> language as well, so that half of it isn't irrelevant to me no matter
>> which one I choose. How should I know which one is best for me, anyway,
>> if I'm new to the framework?
>
> These are all points and it's one of the things that's been nagging me
> about the goal of template language neutrality. Some benefits though:
>
> * as you mentioned: separation of concerns
>
> * evolution potential: we'd not be locked into ZPTs forever
>
> * ability to reuse existing code surrounding Buffet (or Smorgasbord). A
> whole range of template languages become available.
>
> * Grok/Zope 3 can "get out of the template language business"
We seem to be wanting to get out of a lot of businesses these days. I
still prefer ZPTs to all other templating solutions I've used and looked
(though I haven't spent much time with Genshi yet).
> I actually have two goals here:
>
> * template language neutrality would be good from an architecture
> perspective
True.
> * I want to move away from ZPT as Grok's template language.
Really?
I think it's something that we should give very careful thought to. ZPT
is the modus operandi in the Zope (2 + 3 + Plone) world. We may find
there are beneficial synergies here (for example in terms of form
widgets, particular viewlets and so on).
> I'd be interested in seeing whether we can use Genshi. It's conceptually
> similar to ZPT. It doesn't support path expressions, but I am thinking
> more and more path expressions are hurting us more than they gain us.
> They're shorter, yeah, but only because python expressions in ZPT
> require you to type: 'python:'! More readable? More comprehensible? I am
> skeptical. (genshi incidentally does make foo.bar and foo['bar'] mean
> the same thing, if I recall correctly)
If the benefits of a different templating language are not very strong,
I think we need to be careful. We could end up "stick in the middle"
where Zope developers feel uneasy about an alien templating language and
non-Zope developers feel uneasy about various Zopeisms. :)
I'm not saying it's a bad idea, only that it's not one to take lightly.
> One of the reasons I advocate template language neutrality is so we can
> get in a new template language *at all*. If we simply replace ZPT with
> Genshi, our code will break. That's rather too drastic.
True.
> I think Grok should do the following:
>
> * become template language neutral
>
> * promote 1 template language in all its examples and own codebase.
>
> * offer an advanced usage where you can throw in templates in other
> languages. It would be best if we could do this on the Zope 3 level
> itself, but that's probably a major assignment we can't take on, so we
> may end up doing it for Grok.
Broadly, I agree with those.
Martin
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