[Zope-dev] Sorting/Reversing dtml-in with URL arguments

[Duncan Booth]

> Is it possible to set the sort order and reverse flags on
> a dtml-in tag using URL arguments or REQUEST variables?
Someone asked a while back about specifying the sort key 
dynamically. you can find my response in the mailing list archives 
(dated 1st Feb 2000, 09:50) as it has a few ideas that may be 
useful to you.

> For example, sorting "employees" by "name" in index_html 
> would be something like:
> 
>     index_html?sort
> for 
> 
>    <dtml-in employees>
>      ...
>    </dtml-in>
>     
> 
In this case you could try (untested code):
<dtml-let emp=employees>
   <dtml-if sort><dtml-call "emp.sort()"></dtml-if>
   <dtml-if reverse><dtml-call "emp.reverse()"></dtml-if>
   <dtml-in emp>
      ...
   </dtml-in>
</dtml-let>

Provided 'employees' sorts naturally this may be all you need.
Sometimes it may be safer to copy the list before sorting it. I found 
this out the hard way once when I sorted what I thought was a 
copy of PARENTS, it sorted the original PARENTS list and some 
really weird things happened to variable lookup. Most lists may be 
copied thus:
  <dtml-let emp="employees[:]">...</dtml-let>

If you need to sort on a specific field within employees see my 
earlier posting as above.
If the data is in a database use the sql ORDER BY construct to do 
the sorting.

-- 
Duncan Booth                                             duncan@dales.rmplc.co.uk
int month(char *p){return(124864/((p[0]+p[1]-p[2]&0x1f)+1)%12)["\5\x8\3"
"\6\7\xb\1\x9\xa\2\0\4"];} // Who said my code was obscure?
http://dales.rmplc.co.uk/Duncan