ZopeLABS - Using non-declared variables on DTML

import string for var in vars: if context.REQUEST.has_key(var): t = context.REQUEST[var] if same_type(t, ""): # if it's a string, strip whitespace from it t = string.strip(t) context.REQUEST.set(var, t) else: context.REQUEST.set(var, None)

Don't need to predeclare to use in dtml-if by pup - 2001-08-14

In DTML, the statement

  <dtml-if "varname == 'hello'">

will raise an exception if varname isn't defined, but

  <dtml-if varname>

works fine; true if defined & true, false if not defined
or not true.

So, there's no need to "predeclare" variables just to use
them in dtml-if testing.

If you need to check something about a variable, and can't
be sure if its declared or not, you can use this:

  <dtml-if "varname and varname == 'Hello'">

which will not raise an exception if varname is not declared.


BTW, if you work frequently w/variables that may or may not
exist, and want to set default values if they don't exist,
dtml-set (an add-in) is great. You can say things like:

  <dtml-set varname="'Hello'" optional>

rather than the wordy

  <dtml-unless varname>
    <dtml-call "REQUEST.set('varname', 'Hello')">
  </dtml-unless>

Re: Don't need to predeclare to use in dtml-if by Wolfox - 2001-08-14

Uh... in fact I only did this because the following statement:

<dtml-if "send and not (name and emails and memo)">

failed with a NameError when send was not declared. Are you sure it should work? It didn't here.