DTML peek

As promised, I took the red-wire through Zope DTML
and came with sort of synthesis which I hope to inspire
some (new) ideas:

General:
I'm not sure I understood what's the exact semantic of the
PTE (PHP Template Engine). Is it intended to be used in the
PHP manner
 {{<-delim __meta-keyword__ delim->}}
or 
 {{TAG}}[content {{/TAG}} ]?
I would prefer `a template markup language' to a ``s/$foo/'bar'/''

Following are some excerpts from Zope's DTML documentation
In my dreams, things would happen similarily, but...

syntax:
 <dtml-tag attr1="value1" attr2="value2" ...>
 
 sigleton: <dtml-tag ...>
 duplex  : <dtml-tag ...> .* </dtml-tag>

attributes:
  name - if not present then the first ecountered atom is the name
       <dtml-var name="foo"> eq <dtml-var foo>
       The name can also de a function name, or a template name (in
which
       case it is first resolved then fetched in place)
       Also if it is a function, the result is cached for that scope
       <dtml-if expensiveCall>
         <dtml-var expensiveCall> <!--fetched from cache-->
        </dtml-if> <!--end of cache scope-->

  expr - the expression is evaluated and the result returned
       It's enclosed in double quotation marks
       it can make use of a special variable `_', the global namespace

  fmt  - a format for the containing data (e.g. useful for date style)
       can be a custom one (a function)
        e.g. <dtml-var date fmt=DayOfWeek> calls DayOfWeek with the
value of date
       supports C style descriptors 
        e.g <dtml-var cost fmt-"$%.2d" null='n/a'>
         
  null - just as `default' keyword (value when variable is null)
  size - maximum size
  etc  - when truncating, what string to be appended (default is `...')
       e.g <dtml-var spam size=10 etc="...">
  
Other attributes with no arguments:
  lower, upper,capitalize - obvious
  spacify - something like s/_/ /
  thousand_commas - when the value is a number insert commas at every
three digits
  html_qoute , url_quote - special chars 2 entities
  newline_to_br - do nl2br() on the value

So, I would have liked something like <php-var> in PTE

Other cool stuff : 
  REQUEST, RESPONSE objects (also present in ASP, servlets)
  This is OT maybe, or maybe it should go in PEAR implemented on 
  a higher layer, I dunno

Example:
default document source (modified from the docs)
<dtml-var standard_html_header>
<h2><dtml-var document_title></h2>
this is <dtml-var document_id> document. <br>
<dtml-var standard_html_footer>

The standard_* stuff are DTML Methods describe at top level and aquired
by
lower documents. This can eventually be customized in a config file or
imported as separate templates.

A question here: I guess `include' just gets the template w/o
`resolving' it
Can  we also have `import' to get in a template already parsed?


Conditional tags : 
 <dtml-if>, <dtml-unless> - obvious

Iterative insertion: <dtml-in>
  e.g. 
   <table>
    <tr>
      <th>Name</th>
      <th>Phone</th>
    </th>
    <dtml-in employees sort=name>
     <tr>
       <td><dtml-var name></td>
       <td><dtml-var phone></td>
     </tr>
    </dtml-in>
   </table>

  To avoid an empty table:
    <dtml-if employees>
      (same as above)
    <dtml-else>
     No Employees
    </dtml-if>
   (tip: but dtml-in has also an dtml-else, in case the set is empty!)

special  variables are defined within dtml-in scope:
 sequence-start, sequence-end - (boolean) first/last element in set
 sequence-item, sequence-key  - current item, the key associated w/ the
item
 sequence-index - the index of the current item, 0 based

dtml-in attributes (some of): 
  sort - sort the sequence of objects (by attribs values)
  mapping - (no args) sais the items are mapping objects
 batch processing related (also  variables for batch processing)

dtml-with tag : for easy access to objects (just like in JavaScript,
AFAIK)
dtml-let  tag : (multiple) assignment
dtml-call tag : function calls
  e.g. <dtml-call "addDocument('foo.html',namespace(skin='puffy'))">

Exception handling with {dtml-try,dtml-except,dtml-raise}
  e.g. 
   <dtml-try>
     cost per unit: $<dtml-var expr="_.float(total/units)">
     <dtml-except ZeroDivisionError>
     cost per unit: N/A
   </dtml-try>
(exceptions are tabu in PHP, though one still can implement an 
`emulator')

Commenting tags: <dtml-comment> ignored </dtml-comment>

The super-dooper dtml-tree:
simplest:    <dtml-tree> <dtml-var id> </dtml-tree>
By default, displays branches and sub-branches of an object, found by
calling tpValues on the object being displayed (the function can be
customized)

attribs(some): 
branches - name of the method used to find subobjects
branch_expr - expression evaluated to find subobjects
leaves - document used to expand subobjects that do not have
sub-branches
sort - sort the branches
Also some variables are set within dtml-tree scope:
tree-item-expanded, tree-item-url, tree-root-url, tree-level,
tree-colspan

another cool tag : dtml-sendmail
e.g.
 <dtml-sendmail smtphost="my.host.com">
 To: PHP-TPL <<dtml-var phptpl>>
 From: me <<dtml-var me>>
 Subject: <dtml-var subject>
 
 <dtml-var body>
 </dtml-var sendmail>

attribs:
 mailhost - an alternate MailHost object (defined by Zope)
 smtphost - outgoing server
 port - default 25
 mailto - (list of) recipient(s)
 mailfrom - sender
 subject  - obvious
 
For attachments, there is dtml-mime
attribs: 
type - MIME type
disposition - set disposition header
encode - default base64, none if set to 7bit
e.g.
 <dtml-sendmail 
    mailfrom="[email protected]" mailto="[email protected]"
    subject="missing `u' at line 22" smtphost="mightyqmail.com"
    port="8025">
 <dtml-mime type=text/plain encode=7bit>
 Hey, you fotgot your lipstick at home, I attached it
 in case you need it later today :-P
 <dtml-boundary 
   type=application/x-lipstick
   disposition=attachment encode=base64>
   <dtml-var binary_lipstick>
 </dtml-mime>
 </dtml-sendmail>

As far as I can see, most of the ppl involed in this discussion
are biased toward the braces notation, which I don't really like, so
my rates are low, anyway hope you might get some ideas from DTML.

I've been peeking into the python source, to see how it is actually
doing the stuff, but I dunno what can be of interest from them,and also
that nobody would agree with my joke of posting python code :-)

bye.
-- 
CIMPOESU Teodor, Web Programmer
 @ DIGICOM S.A. Bucharest, Romania
 @ Internet, site development
 @ see http://internet.digiro.net/