Re: [Haskell-cafe] Graphical representation of Haskell code

Hi, For Reekie's Visual Haskell, see http://ptolemy.eecs.berkeley.edu/~johnr/papers/visual.html Also take a look on the CAL language (http://openquark.org/Open_Quark/Welcome.html "Welcome to the (...) Open Quark Framework for Java, and the lazy functional language CAL." AFAIK, the CAL language is Haskell alike and have a nice editor!! Some papers that might be of interest: VEX: W. Citrin, R. Hall, and B. Zorn. Programming with visual ex- pressions. In VL ’95: Proceedings of the 11th International IEEE Symposium on Visual Languages, page 294, Washington, DC, USA, 1995. IEEE Computer Society. Pivotal Keith Hanna. Interactive Visual Functional Programming. In S Peyton Jones, editor, Proc. Intnl Conf. on Functional Programming, pages 100–112. ACM, October 2002. Visual Haskell Hideki John Reekie. Realtime Signal Processing – Dataflow, Visual, and Functional Programming. PhD thesis, University of Technology at Sydney, 1995. VPF Joel Kelso. A Visual Programming Environment for Functional Languages. PhD thesis, Murdoch University, 2002. Visual Lambda Laurent Dami and Didier Vallet. Higher-order functional composition in visual form. Technical report, University of Geneva, 1996. best regards Miguel Vilaça A 2010/03/24, às 23:30, Dupont Corentin escreveu:

Hello, Very interresting. Visual Haskell seems to be very close to the thing i imagined. Mihai what do you think? Unfortunatly i cannot find it on the web! There is something for MS Visual Studio but i don't think this is the same...

Corentin

On Thu, Mar 25, 2010 at 12:07 AM, Miguel Vilaca wrote: Hi all,

Concerning INblobs, it's again online; a fire damaged the cable that links the university to the world!! I don't update the tool for a long time... but I'll take a look on that.

Concerning visual functional programming, see this small chapter of my thesis about some of the existing languages.

There are more subtleties on the visual side than those expected!!

If you also consider debugging tools, take a look on Ghood http://hackage.haskell.org/package/GHood

best regards Miguel Vilaça

A 2010/03/23, às 05:31, Ronald Guida escreveu:

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On Mon, Mar 22, 2010 at 7:02 PM, Dupont Corentin wrote:

...

Hello, I’m relatively new to Haskell. I’m wondering if it exist a tool to graphically represent Haskell code. ... Let’s try to do it on a simple example, as an exercise: f = Map (+1)

Your graphic for "f = map (+1)" seems much more complex than the corresponding code. I would agree with Ivan Miljenovic:

...

I'm of the opinion that unless you just use it on small snippets, the generated images will be too large and unwieldy.

The first question I would ask is /why/ would you like to visualize some Haskell code? If you want to see the high-level structure of a complex program, try SourceGraph. (I have never used it though.)

On the other hand, if you are trying to visualize Haskell as part of your efforts to learn the language, then I believe it would be best to draw diagrams by hand, rather than relying on an automated tool. The kinds of things that you'll want to depict are probably going to vary considerably, depending on what you're trying to understand.

Consider a few different implementations of the "map" function:

-- version 1: recursion map1 :: (a -> b) -> [a] -> [b] map1 f [] = [] map1 f (x:xs) = (f x) : map1 f xs

-- version 2: fold map2 :: (a -> b) -> [a] -> [b] map2 f = foldr ((:) . f) []

-- version 3: continuation passing style map3 :: (a -> b) -> [a] -> [b] map3 f xs = map' (\x y -> f x : y) xs where map' k [] = [] map' k (y:ys) = k y (map' k ys)

-- version 4: list comprehension map4 :: (a -> b) -> [a] -> [b] map4 f xs = [f x | x <- xs]

-- version 5: list monad map5 :: (a -> b) -> [a] -> [b] map5 f xs = xs >>= (return . f)

These all do exactly the same thing, but each one uses different techniques. If I'm trying to learn (or teach) Haskell, I would probably need a slightly different visual "language" for each one in order to capture the most relevant concepts in a useful way. How would you visualize them?

@Mihai Maruseac: I think a visual debugger would be a wonderful idea. You may want to consider how a visual debugger would work with each of these versions of map.

:-) You might also consider several versions of factorial :-) http://www.willamette.edu/~fruehr/haskell/evolution.html

-- Ron _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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