define tag with optional parameter

[Axel Koehler <nospam@thanx>]

Hello,

I need a tag definition with an optional parameter.

The tag should give  an alternate  result in the case
that the parameter exist. 

I mean a structure like:

<define-tag side_begin>

If exist (parameter) 
  do blabla blub
else 
  do something completly different
end

</define-tag>

Greetings
Axel Koehler
___________________________________________________________________________
Axel K"ohler,                                            Tel: 030-314 73352
TU Berlin  FB 2  FR 0-1              Franklinstr. 28-29        10587 Berlin

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