Hi there,
I have the following snippet:
data Volume = Volume { name :: String
, mount :: String
, size :: String
, fs :: String
, mbr :: Bool
} deriving (Show, Eq)
defaultVolume :: Volume
defaultVolume = Volume { name = ""
, mount = ""
, size = ""
, fs = "ext4"
, mbr = False
}
parseOptVols :: String -> Volume
parseOptVols s = parseChain (defaultVolume, s)
where
parseChain = parseMBR . parseFS . parseSize . parseMount . parseName
parseName (vol, s) = (vol {name = getThis s}, getNext s)
parseMount (vol, s) = (vol {mount = getThis s}, getNext s)
parseSize (vol, s) = (vol {size = getThis s}, getNext s)
-- fs and mbr are optional
parseFS (vol, "") = (vol, "")
parseFS (vol, ',':s) = (vol, s)
parseFS (vol, s) = (vol {fs = getThis s}, getNext s)
parseMBR (vol, "t") = vol {mbr = True}
parseMBR (vol, _ ) = vol
getThis = takeWhile (',' /=)
getNext = saveTail . dropWhile (',' /=)
saveTail :: [a] -> [a]
saveTail [] = []
saveTail (_:xs) = xs
What it basically does is parse a string (handed over from the
command line) like "boot,/boot,256M,ext3,t" and populates a Volume
instance with this. The last two fields are optional.
I like testing and coming from an object-oriented background unit
testing is the most comfortable to me. But I wonder if there is some
smart way to make QuickCheck produce test cases. I would need some
generator for this which produces a pattern like
"name,mount,size,fs,mbr" eventually leaving "fs" and/or "mbr" empty and
sometimes omitting both commas or just one of them. And I also need
access to these fields in order to be able to compare them with the
resulting Volume instance. I can see how to achieve the former somehow,
but I don't have any clue how to achieve the latter.
Any hints? Or is this simply not a nail for the QuickCheck-hammer?
Regards,
Thomas Bach.
PS: Any advice on how to improve the code above is highly appreciated as
well.
