On Fri, 08 Aug 2014 17:52:38 +0200, Dominick Samperi wrote:

If I recall correctly the Leksah IDE shows GHC reduction step-by-step (using GHC debug info). Unfortunately, the last update was in 2012, so it appears that it has not been following the latest GHC releases.

Leksah still works, but it is not finished; it is only possible to step per (sub)expression, no stepping to the end of a function. The debugger has therefore a very limited use. I hope that a group of people will continue the development, an application like that is too big for one person. Regards, Henk-Jan van Tuyl -- Folding@home What if you could share your unused computer power to help find a cure? In just 5 minutes you can join the world's biggest networked computer and get us closer sooner. Watch the video. http://folding.stanford.edu/ http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming --

Of course, thanks! Also, the code is open source and can easily be used in other courses, that page is just our example. JP On Fri, Aug 8, 2014 at 2:35 PM, Kim-Ee Yeoh wrote:

On Fri, Aug 8, 2014 at 12:30 PM, Jan Paul Posma wrote:

...

Last weekend my friend Steve and I did a small project for visualising Haskell function execution in the browser. It's meant to be used in education, and uses a tiny custom parser. I figured it could be of interest for anyone here learning or teaching Haskell: https://stevekrouse.github.io/hs.js/

Mind if I suggest posting to the haskell reddit /r/haskell ?

Tons of people would find it useful there and share it forward.

-- Kim-Ee

On 2014-Aug-09, Jerzy Karczmarczuk wrote:

Jan Paul Posma mailto:me@janpaulposma.nl> wrote:

...

Last weekend my friend Steve and I did a small project for visualising Haskell function execution in the browser. It's meant to be used in education, and uses a tiny custom parser. I figured it could be of interest for anyone here learning or teaching Haskell: https://stevekrouse.github.io/hs.js/

Indeed, this is a nice, and potentially useful initiative, thanks.

I have some observations, though.

1. Before its "wide distribution" as suggested by Kim-Ee, it would be nice to provide a minimum documentation on the project page.

2. It is not always clear what is the relation between the work of the system, the expression expansion, and what Haskell REALLY does. For, say: (foldr plus 0 [1 2 3 4 5]) the development/reduction depends on what you click. You may get

(plus1(plus2(foldrplus0[3 45]))) or (1+(foldrplus0[2 345]))

and a beginner might have serious problems to understand what really happens in a true Haskell program.

3. The system accepts typing abominations, say, (foldlplus[][1 234 5]) and joyfully develops the structure, which cannot be finally reduced.

4. I don't understand the relation between the typing and the behaviour. I tested foldl with my own function put into the function editor: const x y = x without type declaration. The expression is expanded, but never reduced, const remains in the final expression. When const type is declared, it is reduced.

5. I tried to define my own recursive function (a factorial) and test it replacing one of the standard examples. This breaks the system. If it is not allowed, please say so explicitly. If I did something silly, please see my point (1).

From the pink error messages I'm seeing today (though I don't remember seeing them yesterday when I tried something similar), it looks like the * operator is not supported; the only numerical operators are + and -

My best regards, and thank you once more.

Jerzy Karczmarczuk Caen, France

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

-- Gregory D. Weber, Ph. D. http://mypage.iu.edu/~gdweber/ Associate Professor of Informatics Tel (765) 973-8420 Indiana University East FAX (765) 973-8550