Where can you put def ines?

[Mark Summerfield]

I want to do something like this:

def @Scene left x right y {
    @Section
      @Title { x }
    @Begin
    @Include { y }
    @End @Section
}

Example of use:

{ The One Where Def Actually Works } @Scene { def.lt }

I have tried copying book to mybook and putting it where the mydefs include 
goes; I have tried putting it in mydefs; I have tried various import lines 
above the def line. Basically I don't understand how this all works (and 
yes I've read all the docs, so maybe I'm obtuse!).

For the moment I'm using a macro pre-processor to do the equivalent textual 
substitution, but surely this is possible in lout? 

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