DTML Basics (part 2) - Deeper And Deeper
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For the adventurous amongst you, DTML also lets you "nest" conditional statements - for example, this is perfectly valid DTML code.

<dtml-if expr="day == 'Thursday'">

	<dtml-if "time == '12'>

             	<dtml-if "place == 'Italy'">

                       How about some pasta for lunch?                

		</dtml-if>

	</dtml-if>

</dtml-if>

But you'll agree that is both complex and frightening. And so, in addition to the comparison operators I've used so liberally thus far, Python also provides the "and", "or" and "not" logical operators which allow you to group conditional expressions together. The following table should make this clearer.

Assume delta = 12, gamma = 12 and omega = 9



delta == gamma and delta > omega         True



delta == gamma and delta < omega         False



delta == gamma or delta < omega          True



delta > gamma or delta < omega           False



not delta          				False

Given this knowledge, it's a simple matter to rewrite the example above in terms of logical operators:

<dtml-if expr="(day == 'Thursday') and (time == '12') and (place ==

'Italy')">                       		

	How about some pasta for lunch? 

</dtml-if>

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