February 22, 2008
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Tinderbox 4.1: What You See

Tinderbox 4.1 introduces a very interesting new attribute that lets you control what you see when Tinderbox displays a note. It's called the DisplayExpression.

All Tinderbox notes have a Name. The name has two uses:

Sometimes, though, you'd like to change what you see in views. DisplayExpression lets you display more than the Name in views, but leaves the note's name unchanged.

For example, right now I'm setting up a program committee for WikiSym. This is the sort of task lots of researchers need to undertake from time to time. First, I need to imagine who I might like to have on the committee. I make a prototype for Person and a container of possible candidates:

So, I can just jot down names as fast as I can think of them. Each new note is automatically assigned a prototype, and the notes all stay nicely sorted.

But how many people are in the list? I can always check the ChildCount of the container, but I'd like to be able to see this at a glance. So, I add a DisplayExpression to the prototype Person:

$SiblingOrder: $Name

So my list now looks like like this:

1: M. Brillouin

2: H. Lorentz

3: W. Nernst

4: E. Solvay

Doug Miller invented a way to do this in earlier versions of Tinderbox, but his technique meant changing the Name of the note. That can be inconvenient if you need to refer to a note in an agent or an action; the new technique is cleaner and simpler.