Sebastian Fischer schrieb:
Hello Christian,
On Apr 19, 2010, at 4:48 PM, Christian Maeder wrote:
I like to announce a Haskell style scanner at http://hackage.haskell.org/package/scan
Feedback is welcome.
I get lots of "multiple blanks" which I'd rather not "correct".
I often use multiple blanks to achieve vertical layout which is especially useful in combination with lhs2TeX [1] whose polycode mode requires multiple blanks to achieve proper indentation.
This code
instance Eq a => Eq (Maybe a) where Nothing == Nothing = True Just x == Just y = x == y _ == _ = False
This sort of tabular layout is not supported by scan.
triggers this scan output:
scan-test.hs:2:10: up to column 12 multiple (2) blanks scan-test.hs:2:14: up to column 16 multiple (2) blanks scan-test.hs:2:23: up to column 25 multiple (2) blanks scan-test.hs:3:9: up to column 12 multiple (3) blanks scan-test.hs:3:14: up to column 16 multiple (2) blanks scan-test.hs:3:22: up to column 25 multiple (3) blanks scan-test.hs:4:4: up to column 12 multiple (8) blanks scan-test.hs:4:14: up to column 16 multiple (2) blanks scan-test.hs:4:17: up to column 25 multiple (8) blanks
At least you see a regular pattern wrt column position: (12, 16, 25)
I very much prefer the previous indentation over the following version stripped down by scan - (using the hyphen option):
instance Eq a => Eq (Maybe a) where Nothing == Nothing = True Just x == Just y = x == y _ == _ = False
I did not find a way to configure scan to ignore "multiple blanks". Did I miss it?
It isn't yet implemented. Cheers Christian
Sebastian