Re: [Haskell-beginners] Re: [Haskell-cafe] The problem with Monads...
I have written a reference manual for the basic Haskell monad functions, A Tour of the Haskell Monad functions. It contains a lot of examples. You can find it at: http://members.chello.nl/hjgtuyl/tourdemonad.html Wow! I like these examples. I'm a pragmatist, and although Haskell gave me the most intense joy I ever experienced with programming (and also frustrations ;-), I find it extremely difficult to learn it from research papers. But these small examples are exactly what I need, because my brain will easier recognize a pattern match with the specific examples, than with the abstract explanation (and I was pretty good at abstract algebra, but that's 20 years ago, and I filled these 2 decades with lots and lots of imperative and OO hacking ;-). I wish every function in every module in the documentation had an examples link next to the source link, or a link to examples on the wiki or something. I guess the smart computer scientists here will tell me that I need to lift my brain to learn to recognize abstract patterns, but I'm afraid this is not something that is given to all of us, certainly not in the short term. But I still want to enjoy Haskell, so keep the short examples coming :) As far as I know, there is no reference guide for advanced monads, like the Reader, Writer and State monads. -- Regards, Henk-Jan van Tuyl -- http://functor.bamikanarie.com http://Van.Tuyl.eu/ -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The problem with Monads...
On Tue, 2009-01-13 at 12:56 -0200, Rafael Gustavo da Cunha Pereira Pinto wrote: Last night I was thinking on what makes monads so hard to take, and came to a conclusion: the lack of a guided tour on the implemented monads. ... Inspired by the paper Functional Programming with Overloading and Higher-Order Polymorphism, Mark P Jones (http://web.cecs.pdx.edu/~mpj/pubs/springschool.html) Advanced School of Functional Programming, 1995. SO WHAT? So have you read Jones' paper? Or do you have a *concrete* explanation of how it differs from your desired `guided tour'? jcc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The problem with Monads...
Yes, I've read it twice, and it is a nice explanation that yes, the reader monad is an application and is a monad. How do I use it? Why not the function itself? How would the plumbing work in a real world example? BTW, the article is really great as an brief introduction to monad transformers. For the whole concept of monads, my all time favorite is The Haskell Programmer's Guide to the IO Monad by Stefan Klinger. Chapters 14 to 19 of Real World Haskell also have a good introduction on the usage of the monads, but it lacks other monads, like the RWS or the Continuation... See, that is my point. The mathematical concept of monads is very palatable. The idea that monads are either patterns or structures to hide computations in sequence is also very easy to see. But how do we use them? Why should I use a Writer monad when I can use a (a,w) tuple? On Tue, Jan 13, 2009 at 13:51, Jonathan Cast jonathancc...@fastmail.fmwrote: On Tue, 2009-01-13 at 12:56 -0200, Rafael Gustavo da Cunha Pereira Pinto wrote: Last night I was thinking on what makes monads so hard to take, and came to a conclusion: the lack of a guided tour on the implemented monads. ... Inspired by the paper Functional Programming with Overloading and Higher-Order Polymorphism, Mark P Jones (http://web.cecs.pdx.edu/~mpj/pubs/springschool.htmlhttp://web.cecs.pdx.edu/%7Empj/pubs/springschool.html ) Advanced School of Functional Programming, 1995. SO WHAT? So have you read Jones' paper? Or do you have a *concrete* explanation of how it differs from your desired `guided tour'? jcc -- Rafael Gustavo da Cunha Pereira Pinto Electronic Engineer, MSc. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] The problem with Monads...
Jonathan Cast wrote: On Tue, 2009-01-13 at 12:56 -0200, Rafael Gustavo da Cunha Pereira Pinto wrote: Inspired by the paper Functional Programming with Overloading and Higher-Order Polymorphism, Mark P Jones (http://web.cecs.pdx.edu/~mpj/pubs/springschool.html) Advanced School of Functional Programming, 1995. SO WHAT? So have you read Jones' paper? Or do you have a *concrete* explanation of how it differs from your desired `guided tour'? To give a specific example, a few weeks ago I wanted an explanation of the 'pass' function and couldn't find it in that paper. Ganesh == Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html == ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] The problem with Monads...
On Tue, 2009-01-13 at 16:22 +, Sittampalam, Ganesh wrote: Jonathan Cast wrote: On Tue, 2009-01-13 at 12:56 -0200, Rafael Gustavo da Cunha Pereira Pinto wrote: Inspired by the paper Functional Programming with Overloading and Higher-Order Polymorphism, Mark P Jones (http://web.cecs.pdx.edu/~mpj/pubs/springschool.html) Advanced School of Functional Programming, 1995. SO WHAT? So have you read Jones' paper? Or do you have a *concrete* explanation of how it differs from your desired `guided tour'? To give a specific example, a few weeks ago I wanted an explanation of the 'pass' function and couldn't find it in that paper. Ganesh Several years ago I documented all the (basic) monads in the mtl on the (old) wiki. http://web.archive.org/web/20030927210146/haskell.org/hawiki/MonadTemplateLibrary In particular, http://web.archive.org/web/20030907203223/haskell.org/hawiki/MonadWriter To respond to the essential point of Rafael's initial claim, Wadler's papers The Essence of Functional Programming and/or Monads for Functional Programming have exactly what he wants. These are the papers that I recommend to anyone who is learning about monads. http://homepages.inf.ed.ac.uk/wadler/topics/monads.html Please, we do not need the 101st monad tutorial when there was an adequate one made almost two decades ago. While I'm not saying that this is the case here, I suspect that many people don't read those papers because 1) they haven't heard of them and 2) they are papers and thus couldn't possibly be readable and understandable (which also partially causes (1) as people just don't think to look for papers at all.) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The problem with Monads...
I didn't knew Wadler's papers (I save all papers I read into a external USB HD, so I can read them later!), and at a first glance it is really good. Then again, instead of creating another monad tutorial, what about a Haskell monads reference guide, and some worked examples? Some of this work could even be attached to the library documentation. Regards Rafael On Tue, Jan 13, 2009 at 15:27, Derek Elkins derek.a.elk...@gmail.comwrote: On Tue, 2009-01-13 at 16:22 +, Sittampalam, Ganesh wrote: Jonathan Cast wrote: On Tue, 2009-01-13 at 12:56 -0200, Rafael Gustavo da Cunha Pereira Pinto wrote: Inspired by the paper Functional Programming with Overloading and Higher-Order Polymorphism, Mark P Jones (http://web.cecs.pdx.edu/~mpj/pubs/springschool.htmlhttp://web.cecs.pdx.edu/%7Empj/pubs/springschool.html ) Advanced School of Functional Programming, 1995. SO WHAT? So have you read Jones' paper? Or do you have a *concrete* explanation of how it differs from your desired `guided tour'? To give a specific example, a few weeks ago I wanted an explanation of the 'pass' function and couldn't find it in that paper. Ganesh Several years ago I documented all the (basic) monads in the mtl on the (old) wiki. http://web.archive.org/web/20030927210146/haskell.org/hawiki/MonadTemplateLibrary In particular, http://web.archive.org/web/20030907203223/haskell.org/hawiki/MonadWriter To respond to the essential point of Rafael's initial claim, Wadler's papers The Essence of Functional Programming and/or Monads for Functional Programming have exactly what he wants. These are the papers that I recommend to anyone who is learning about monads. http://homepages.inf.ed.ac.uk/wadler/topics/monads.html Please, we do not need the 101st monad tutorial when there was an adequate one made almost two decades ago. While I'm not saying that this is the case here, I suspect that many people don't read those papers because 1) they haven't heard of them and 2) they are papers and thus couldn't possibly be readable and understandable (which also partially causes (1) as people just don't think to look for papers at all.) -- Rafael Gustavo da Cunha Pereira Pinto Electronic Engineer, MSc. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-beginners] Re: [Haskell-cafe] The problem with Monads...
On Tue, 13 Jan 2009 19:35:57 +0100, Rafael Gustavo da Cunha Pereira Pinto rafaelgcpp.li...@gmail.com wrote: I didn't knew Wadler's papers (I save all papers I read into a external USB HD, so I can read them later!), and at a first glance it is really good. Then again, instead of creating another monad tutorial, what about a Haskell monads reference guide, and some worked examples? Some of this work could even be attached to the library documentation. Regards Rafael I have written a reference manual for the basic Haskell monad functions, A Tour of the Haskell Monad functions. It contains a lot of examples. You can find it at: http://members.chello.nl/hjgtuyl/tourdemonad.html As far as I know, there is no reference guide for advanced monads, like the Reader, Writer and State monads. -- Regards, Henk-Jan van Tuyl -- http://functor.bamikanarie.com http://Van.Tuyl.eu/ -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
