Who said Zope was getting more like Perl than Python: There's more than one way to do it ;) ----- Original Message ----- From: "Chris McDonough" <chrism@zope.com> To: "Chris McDonough" <chrism@zope.com> Cc: "John Adams" <jadams@inktomi.com>; <zope@zope.org> Sent: Wednesday, May 08, 2002 4:44 AM Subject: Re: [Zope] Why is it so hard to do simple things?
Whoops. I had it wrong last time around. One more time, with feeling:
<dtml-let button_value="REQUEST.get('perm_or_temp', 'P')"> <INPUT TYPE='RADIO' NAME=perm_or_temp VALUE="P" <dtml-if "button-value=='P'"> CHECKED</dtml-if> > Permanent <INPUT TYPE='RADIO' NAME=perm_or_temp VALUE="T" <dtml-if "button-value=='T'> CHECKED</dtml-if> > Temporary </dtml-let>
.. or ..
button_value = context.REQUEST.get('perm_or_temp', 'P') possible = {'P':'Persistent','T':'Temporary'} items = possible.items() items.sort() for key, value in items: checked = (key == button_value) and ' CHECKED' or '' print ("<input type=radio name=perm_or_temp VALUE='%s'%s> %s" % (key, checked, value)) return printed
.. and a bonus alternate DTML implementation mirroring the Python one ..
<dtml-let button_value="REQUEST.get('perm_or_temp', 'P')" possible="{'P':'Persistent','T':'Temporary'}" items="possible.items()"> <dtml-call "items.sort()"> <dtml-in items> <dtml-let "checked = (_[sequence-key] == button_value) and ' CHECKED' or ''> <INPUT TYPE='RADIO' NAME=perm_or_temp VALUE="<dtml-var sequence-key>" <dtml-var checked>> <dtml-var sequence-item> </dtml-let> </dtml-in> </dtml-let>
Chris McDonough wrote:
John Adams wrote:
If I was doing this in perl it'd be quite easy; I could check the query variable, and act on it -- but now I have to deal with things like not being able to even examine the variable without throwing an exception, and the fact that Python doesn't short-circuit blows.
i.e. You can't examine something like:
if (hasattr(request,'perm_or_temp') and request.perm_or_temp == 'P')
Python does indeed short-circuit this statement and it will work as you seem to expect. Have you tried it?
In DTML, here is something that will do what I think you want.
<dtml-let button_value="REQUEST.get('perm_or_temp')"> <INPUT TYPE='RADIO' NAME=perm_or_temp VALUE="P" <dtml-if "button-value=='P' or button_value==None"> CHECKED</dtml-if> > Permanent <INPUT TYPE='RADIO' NAME=perm_or_temp VALUE="T" <dtml-if "button-value=='T'> CHECKED</dtml-if> > Temporary </dtml-let>
There's a million variations on this, some better than others. In Python one way to do this would be as:
button_value = context.REQUEST.get('perm_or_temp') checked_button = {None: 'P', 'P':'P', 'T':'T'}.get(button_value) for value in ['P', 'T']: checked = (value == checked_button) and ' CHECKED' or '' print ("<input type=radio name=perm_or_temp VALUE='%s'%s>" % (value, checked)) return printed
You could do something similar to this in DTML if you wanted as well. Since there are only a couple of possible values, it's probably easier just to spell it all out in this case.
I'd suggest picking up the "Learning Python" O'Reilly book to learn basic idioms like this. The thing you were missing was that dictionary-like objects (of which REQUEST is one) have a get method that returns None if nothing of that key exists in the dictionary on a lookup.
-- Chris McDonough Zope Corporation http://www.zope.org http://www.zope.com "Killing hundreds of birds with thousands of stones"
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