Thank you very much for your fast response!
Ok, that is now changed, but everything else in my program is expecting
Catalogue without IO. Is there a way to change IO Catalogue into Catalogue?
Henning Thielemann wrote:
On Thu, 8 May 2008, Mark Wallsgrove wrote:
Problem now is reading the data back into the program. When I read the
data
back into the program it comes as IO [Track]. This is the code I have
been
using to load the data:
loadData :: String -> Catalogue
loadData fileName = do x <- readFile fileName
return (read x :: Catalogue)
type should be
loadData :: String -> IO Catalogue
But using plainly 'read' may not satisfy you, because the program will
abort unrecoverably if the file has corrupt content. You may want to use
'reads' and check manually if parsing was successful:
case reads x of
[(cat, "")] -> return cat
_ -> fail "corrupt file content"
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