[Haskell-beginners] How to solve this using State Monad?

[Miguel Negrao]

A 31/05/2012, às 17:18, Ertugrul Söylemez escreveu:

> Miguel Negrao <miguel.negrao-lists at friendlyvirus.org> wrote:
> 
>> Because of those posts I spent my morning reading about arrows which
>> seems a quite interesting concept, although couldn’t yet see what is
>> best for ( I would be curious to learn it in order to try out Yampa).
>> I have to say that the resources I found to learn about arrows on the
>> net were a bit disorganized. This page is really well done
>> http://en.wikibooks.org/wiki/Haskell/Understanding_arrows but then
>> because I don’t know much about parsers I couldn’t really progress
>> through the second half.
> 
> I have started an arrow tutorial which many people found easy to follow.
> It's not finished yet, but since so many people found it useful I'm
> sharing that unfinished tutorial:
> 
>    <http://ertes.de/new/tutorials/arrows.html>
> 
> It answers the most important questions:  What?  Why?  How?  To some
> extent it also answers:  When?  But I have to work on that question.
> The basics of the automaton arrow are covered, but when I find time I
> will extend the tutorial to cover Auto in full.  Finally I also intend
> to cover a powerful generalization of Auto:  the wire arrow, which is
> the basis of the Netwire AFRP library.

I found your tutorial very enlightening. I think I kind of got more or less the main idea, but I need to try some code to get a feel for it.  I mostly program audio related stuff and arrows seem perfect for defining audio synthesis (I already saw some attempts at this with Yampa). I see a lot of similarities between arrows and the Faust audio synthesis languages (perhaps it’s the same core idea ?) http://faust.grame.fr/. 

best,
Miguel Negrão