I'm just starting out with Haskell, and I could use some help. I'm
trying to create a random list and print it out, which seems simple
enough, but has been giving me problems. Here's what I have:
module Main
where
import IO
import Random
randomList :: Random a => a -> a-> [IO a]
randomList lbound ubound = randomRIO(lbound, ubound) :
randomList lbound ubound
main = do
myRandomList <- sequence(randomList(0::Int 255))
putStrLn(show(take(10 myRandomList)))
-----
So, I have tried to make a randomList action which defines an infinite
random list, bounded by lbound and ubound. It seems that to print
this, I need to convert between randomList, which is of type [IO a] to
something like IO [a], which is what sequence should do for me. Then
I just want to print out the first 10 elements.
I'm currently getting the error "Only unit numeric type pattern is
valid", pointing to 0::Int 255 in the code. I'm not sure what this
means.
I'm sure I'm looking at this the wrong way, since I'm new to Haskell
and haven't quite wrapped my head around it yet. Maybe you can fix
the problem by showing me a more Haskell approach to creating a random
list and printing it... =)
Thanks!
- bryan catanzaro
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