Integrating Smarty with Content Management System, questions and design issues (long posting)

Hello everyone, I am involved in the development of a PHP based content management system. We have already got a stable engine for merging content and design at runtime and do some caching of the results. However, our templates still require some PHP coding experience, maybe even too tricky for (coding unexperienced) web designers >:). Thus, we chose to integrate a template engine which can be extended to fit our needs and which requires no PHP coding in the templates at all. Of course, this implies that we have to be able to hide our API calls in some custom tags. Currently, I am trying to make a feasibility study on integrating Smarty with our system. I have played around quite a bit now and have some questions. Maybe you have had similar problems and would like to share your experiences, solutions or workarounds. Should we find that Smarty is our best option, we would of course contribute our modifications or extensions to the project. 1. Template "inheritance" By now, we've implemented templates as PHP classes. Basically, there's a base class (lets say, "Template") which provides a "draw" method, which, in turn, calls methods like $this->head(), $this->navigation(), $this->mainContent()... Each of these is responsible for outputting a certain part of the page, however, this subdivision is completely up to you. This allows you to subclass your base template to override a specific part of your pages. Say you would like to change your navigation style, just subclass your base template and override the navigation() method. You just have to implement the "different" parts with no unnecessary code replication. Do you see any good way to implement such behavior with Smarty? We could have different templates for the default implementation of different parts (head, navigation, ...) and glue these together with the include directive. However, each of your templates would have to include these subtemplates in the appropriate place; you also could not simply add a new part by adding a method to the base class and calling it from the draw() method. Instead, you would have to change _all_ templates and add the "new" include directive. (Including the "new" part from an already included default file breaks for templates overriding this default file!) 2. Applying modifiers on (custom) functions We would need to implement some custom functions for encapsulating our API calls in Smarty tags. Lets assume we have a custom "tag" used as follows: <h1>{cmscontent field="title"}</h1> <p>{cmscontent field="bodytext"}</p> Now I'd like to give the designer the ability to use Smarty modifiers. However, this is not possible with functions. This would require a change of the parsing process (I assume in _compile_tag in Smarty_Compiler around line 236), as {myfunc|modifier} is interpreted as a custom function "myfunc|modifier" and {myfunc | modifier} is interpreted as a function myfunc with (invalid) arguments. Even more difficult, modifiers are functions and are supposed to take their input as argument and return it modified; custom functions are required to write out their output at runtime. So I do not see a (direct) way to make this work. The problem is that some of the API calls are quite expensive, so I do not want to get everything in advance and assign it to template vars. A workaround would be something like ...{assigncmscontent field="title" var="vtitle"}{$vtitle|upper}, i. e. make the function assign a variable and use this later on. I consider this kind of cumbersome. Any ideas on this? Maybe I misunderstood something and should not use a custom function for this task? 3. (Custom) block functions with block code depending on their result As far as I can see, the current implementation of custom block functions does not allow your block function to set up variables that can be used at run time from within the block code. I would like to hide some kind of "iterator" concept from our API inside the block function, e. g. <ul>{iteratenavigation rootid="123" mode="preorder" var="navelement"} <li>{$navelement.text}</li> <!-- or even -->{cmscontent var=$navelement field="text"} {/iteratenavigation}</ul> The problem is that the code inside the block and its variables are evaluated first and the output is passed to the block function at runtime, so that there is no way of assigning variables in the block function and using them in the block. There is another posting related to this: http://marc.theaimsgroup.com/?l=smarty-general&m=103729427302672&w=29 What was the design motivation for this? I would like to insert code at the compile phase, that is replacing the block tags with code which is executed the same time the block content is interpreted. This way we could encapsulate iterating in the block functions, not only looping over or processing already-evaluated code. I presume I would have to subclass Smarty_Compiler, as it cannot (does not) map a {foo}...{/foo} pattern to compiler functions. However, as the compiler function interface is inappropriate anyway, the (better?) idea is to replace _compile_block_tag and make changes in the last few lines, i. e. do not write out the code to execute the block function at runtime, but instead call the block function at compile time and have it insert real do/while constructs into the compiled template. Of course, this might break compatibility? Where? Any solutions, ideas? [Glad to see you're still with me :)] Maybe I was not always clear enough with my thoughts or have uttered stupid thoughts? However, let me know, as I would be happy with every reply I get :) Btw, the line numbers I gave may be incorrect, as I just saw that there's a new release. Thanks in advance, Matthias