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?<br>
<br>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.<br>
<br>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...<br><br>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? <br>
Why should I use a Writer monad when I can use a (a,w) tuple?<br><br><br><br><div class="gmail_quote">On Tue, Jan 13, 2009 at 13:51, Jonathan Cast <span dir="ltr"><<a href="mailto:jonathanccast@fastmail.fm">jonathanccast@fastmail.fm</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">On Tue, 2009-01-13 at 12:56 -0200, Rafael Gustavo da Cunha Pereira Pinto<br>
wrote:<br>
<div class="Ih2E3d">><br>
> Last night I was thinking on what makes monads so hard to take, and<br>
> came to a conclusion: the lack of a guided tour on the implemented<br>
> monads.<br>
<br>
</div>...<br>
<div class="Ih2E3d"><br>
> Inspired by the paper "Functional Programming with Overloading and<br>
> Higher-Order Polymorphism",<br>
> Mark P Jones<br>
> (<a href="http://web.cecs.pdx.edu/%7Empj/pubs/springschool.html" target="_blank">http://web.cecs.pdx.edu/~mpj/pubs/springschool.html</a>)<br>
> Advanced School of Functional Programming, 1995.<br>
><br>
> SO WHAT?<br>
<br>
</div>So have you read Jones' paper? Or do you have a *concrete* explanation<br>
of how it differs from your desired `guided tour'?<br>
<br>
jcc<br>
<br>
<br>
</blockquote></div><br><br clear="all"><br>-- <br>Rafael Gustavo da Cunha Pereira Pinto<br>Electronic Engineer, MSc.<br>