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I'm toying around with web programming in Haskell. I'm trying to write a
script which GETs an id and returns a couple of random numbers.
Something like this:
cgiMain :: CGI CGIResult
cgiMain = do
inp <- getInput "id"
let gen = parse inp
output $ take 10 (randoms gen)
parse :: Maybe String-> StdGen
parse (Just x) = read x
parse Nothing = undefined
Now I'd like to get a new StdGen, in case no id was supplied to the script.
cgiMain :: CGI CGIResult
cgiMain = do
inp <- getInput "id"
gen <- parse inp
output $ take 10 (randoms gen)
parse :: Maybe String-> IO StdGen
parse (Just x) = return $ read x
parse Nothing = getStdGen
Obviously this doesn't work because I'm trying to do IO inside CGI
(right?). Is there some incantation I can perform to make this possible?
Like
gen <- arcaneMagic parse inp
As you probably have noticed I don't know very much about monads, all I
did until now was reading or writing some files.
Thanks in advance
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