At the LGM 2009 BOF, I remember Oyvind discussing his vision of
something kind of like this.
Since GEGL structures its operations in tree form, what you may want
to think about is that you want to display a tree in a form
understandable by a user.
My personal take is that there probably is a topological sort
algorithm which "effortlessly" leads to an easy to understand
description of the tree in list form. (This list could then be broken
up in "sublists."
No doubt, Oyvind and others (including you) have better ideas.
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