C..4 Cheetah vs. Zope's DTML

For a basic introduction to DTML, visit http://www.zope.org/Members/michel/ZB/DTML.dtml.

Cheetah is faster than DTML.
Cheetah does not use HTML-style tags; DTML does. Thus, Cheetah tags are visible in rendered HTML output if something goes wrong.
DTML can only be used with ZOPE for web development; Cheetah can be used as a standalone tool for any purpose.
Cheetah's documentation is more complete than DTML's.
Cheetah's learning curve is shorter than DTML's.
DTML has no equivalent of Cheetah's blocks, caching framework, unified dotted notation, and #raw directive.

Here are some examples of syntax differences between DTML and Cheetah:

<ul>
<dtml-in frogQuery>
 <li><dtml-var animal_name></li>
</dtml-in>
</ul>

<ul>
#for $animal_name in $frogQuery
 <li>$animal_name</li>
#end for
</ul>

<dtml-if expr="monkeys > monkey_limit">
  <p>There are too many monkeys!</p>
<dtml-elif expr="monkeys < minimum_monkeys">
  <p>There aren't enough monkeys!</p>
<dtml-else>
  <p>There are just enough monkeys.</p>
</dtml-if>

#if $monkeys > $monkey_limit
  <p>There are too many monkeys!</p>
#else if $monkeys < $minimum_monkeys
  <p>There aren't enough monkeys!</p>
#else
  <p>There are just enough monkeys.</p>
#end if

<table>
<dtml-in expr="objectValues('File')">
  <dtml-if sequence-even>
    <tr bgcolor="grey">
  <dtml-else>
    <tr>
  </dtml-if>    
  <td>
  <a href="&dtml-absolute_url;"><dtml-var title_or_id></a>
  </td></tr>
</dtml-in>
</table>

<table>
#set $evenRow = 0
#for $file in $files('File')
  #if $evenRow
    <tr bgcolor="grey">
    #set $evenRow = 0
  #else
    <tr>
    #set $evenRow = 1
  #end if
  <td>
  <a href="$file.absolute_url">$file.title_or_id</a>
  </td></tr>
#end for
</table>

The last example changed the name of $objectValues to $files because that's what a Cheetah developer would write. The developer would be responsible for ensuring $files returned a list (or tuple) of objects (or dictionaries) containing the attributes (or methods or dictionary keys) `absolute_url' and `title_or_id'. All these names (`objectValues', `absolute_url' and `title_or_id') are standard parts of Zope, but in Cheetah the developer is in charge of writing them and giving them a reasonable behaviour.

Some of DTML's features are being ported to Cheetah, such as Cheetah.Tools.MondoReport, which is based on the <dtml-in> tag. We are also planning an output filter as flexible as the <dtml-var> formatting options. However, neither of these are complete yet.