On Sep 6, 2009, at 9:05 PM, David Leimbach wrote:
On Sun, Sep 6, 2009 at 10:08 AM, Eris Discordia
<eris.discordia@gmail.com> wrote:
In this respect rating the "expressive power of C versus LISP" depends
very much on the problem domain under discussion.
Of course. I pointed out in my first post on the thread that "[...] for a person of my (low) caliber, LISP is neither suited to the family of problems I encounter nor suited to the machines I solve them on." I cannot exclude other machines and other problems but can talk from what little I have personally experienced.
I would like to see Haskell fill C's niche [...]
Is it as readily comprehensible to newcomers as C? Are there texts out there that can welcome a real beginner in programming and help him become productive, on a personal level at least, as rapidly as good C textbooks--you know the classic example--do? Is there a coherent mental model of small computers--not necessarily what you or I deem to be a small computer--that Haskell fits well and can be taught to learners? I imagine those will be indispensable for any language to replace existing languages, much more so in case of C.
According to the designer of F# (another functional programming language that takes it's syntax from O'Caml as well as Haskell and even Python), one of the best experiences he'd had was working with a high school student who was able to modify a solar system simulation written in F# with no prior programming experience. (from
http://www.computerworld.com.au/article/271034/)
There's books on F# out there, and F# for Scientists.
There's books on multimedia programming in Haskell out there that also attempt to show programming to newcomers, but I'm not sure any of them really assume no prior programming experience.
I think people learning C get one view of the computer that folks learning assembly really learn to appreciate :-). Folks learning Haskell learn another mental model of programming as well.
My personal belief is that learning new languages makes one think about the languages they are used to in a new light, and can make them better programmers overall.
As you mentioned beginners books for Haskell I couldn't resist plugging Graham Huttons excellent beginners book "Programming in Haskell":
It is based on 10 years of teaching a first year undergraduate course and is certainly accessible I believe. I've taught an undergraduate course myself using it.
There is also the this book which complements Graham's quite well:
I agree with David in that it is asking the wrong question as to whether there is a model of a computer that fits with Haskell. Haskell is based on a different model of computation. Conceptually, Haskell programs are executed by rewriting expressions not by manipulating memory in a machine.
A trivial example:
Here's a function to append a list onto a list:
append :: [a] -> [a] -> [a]
append [] ys = ys
append (x:xs) ys = x:append xs ys
and here we run it (on paper, no machine required :) ) on a some lists by applying the above rules where the match:
Note: [1,2] is syntactic sugar for (1:(2:[]))
append [1,2] [3,4]
= { apply first pattern match equation }
1 : append [2] [3,4]
= { apply first pattern match equation }
1 : 2 : append [] [3,4]
= { apply second pattern match equation }
1 : 2 : [3,4]
= { just syntactic sugar }
[1,2,3,4]
I wouldn't be as bold as to suggest that Haskell should replace C but certainly it is a nice language to use in my opinion. Does it explain how a computer works? No. Does it explain 'computation'? Yes.