[Haskell-cafe] Functional GUI combinators for arbitrary graphs ofcomponents?

Brian Hulley brianh at metamilk.com
Sun Dec 3 09:40:25 EST 2006

Paul Hudak wrote:
>> Brian Hulley wrote:
>>> Anyway to get to my point, though all this sounds great, I'm
>>> wondering how to construct an arbitrary graph of Fudgets just from a
>>> fixed set of combinators, such that each Fudget (node in the graph)
>>> is only mentioned once in the expression. To simplify the question,
> If you consider just Dags, I believe that this question is equivalent
> to asking what set of combinators will allow you to create an
> arbitrary composition of functions that allow sharing inputs and
> returning multiple results.  And I think that one answer to that is
> the set of combinators that make up the Arrow class.  If you want to
> include recursion (i.e. cycles), then you'd have to throw in
> ArrowLoop (although that might only provide a nested form of cycles).
> It's in this sense that Fudgets is analogous to Fruit.

Thanks. Actually thinking more about it I've probably missed the point that 
for a compositional GUI there's no need for a general graph, since each 
view/controller of the underlying model could be encapsulated as a single 
widget (eg fudget or signal transformer) which could be connected to the 
model via a loop which exposes only the model (thus allowing other views to 
be added later).


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