3.1 Controlling $Includes with if/then

[kruegerM]

Is it possible to use logic statements within DTL items such as language, include templates, etc?
I find reference back in the 2.0 developer manual of statements like:
<dtl if ($Text{"Lock"} eq "Lock") { $Data{"Language"} = "en"; }>
But I don't find anything like it in 3.1 documentation
Do such statements still work? If so can they be used to control what template is included, ie;

<dtl if ($Text{"Lock"} eq "Lock") { $Data{"$Include"} = "templateA"; }>

??