
* Heiko Studt
Hi (and hello everybody),
I read the FAQ, I searched down till Nov 2008, but did not find anything. I hope I didn't miss a FAQ or somewhat. (If so, please apologize!)
My (freshly installed) GHCi 6.10.1 runs on Windows XP on Intel Dual Core. I used the .msi of the Webpage some two weeks ago.
I got some strange program as example and tried out - and my ghci died quitly without any helping message.
Here is the original programm: | f x y z = a + b*c + b + fun c | where a = x * y + z | b = c * fun x | c = a * b | fun x = x * x + 1
For testing out in previous of this posting, the following is the very same and had the same problem: | let f x y z = a + b*c + b + fun c where {a = x * y + z; b = c * fun x; c = a * b; fun x = x * x + 1}
The query to die was "f 1 2 3". [...]
Your program loops for the following reason: to compute f, you need to compute c to compute c, you need to compute b to compute b, you need to compute c again! Haskell cannot solve equations (or, at least, not formulated in this way), so it understands definition of f as the rules to compute things like a, b, c. No wonder evaluation of f never terminates. -- Roman I. Cheplyaka :: http://ro-che.info/ "Don't let school get in the way of your education." - Mark Twain