From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Robin Green
No, that's not what I meant at all. I meant that for *many* but not all practical programming tasks, IO is important. Games, GUI office applications, database applications, web applications, etc.
Compilers are atypical in this regard. Something that is perceived as being only useful for a compilers and a few other academic-ish things isn't going to be perceived as very practically useful. -- Robin
Hear, hear. Compilers, and computationally complex programs in general, are atypical. IMO, a lot of programming these days is integration work i.e. shuffling and transforming data from one system to another, or transforming data for reports, etc. Not many programmers write compilers these days :-( (apologies to the Simons, and John Meacham, and anyone else who *has* written a compiler, Haskell or otherwise...) http://www.mcs.vuw.ac.nz/~kjx/papers/nopp.pdf It's good to start with IO. Reading and writing files, parsing and printing (show and read), talking to databases, GUIs, and networking are more-or-less essential activities, and people want to know early on how to do these things. You don't have to introduce the IO monad; just tell people that we separate IO functions from "pure" functions with this special IO type, and, with the "imperative" do-notation, IO code in Haskell looks a lot like IO code in C/Java/.Net. The Really Good Stuff (real monadic programming) can come later. Perhaps there are two different worlds to consider. Teaching Haskell to tertiary students might well be better suited to a style where purely functional programming is explored in some detail before IO and monads are introduced. However, a jobbing programmer evaluating Haskell wants to know how they do the things they're used to doing in other langauges, and if they see the volume of stuff that must be covered before topics like IO, GUIs, and networking, they'll start to look elsewhere... How hard should it be to shove a window on the screen, or select some data from a database? Part of the problem is that we're not just introducing a new language, we're introducing a new paradigm. I can see that a noob would choke if you tried to ram it down their throat all at once. As a comparison, I have some .Net books in front of me, and although they also introduce the language first (declarations, choice, iteration, classes and interfaces), it's pretty trivial stuff and can be skimmed over fairly quickly, and then you quickly get into introspection (reflection), GUIs, IO, databases, and networking. Indeed, the bulk of the book covers these topics. Alistair ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************