Ch11: isSubsequenceOf function is incorrect

[Bassov]

haskell-programming/ch11/AsPatterns.hs

Line 5 in c618817

isSubsequenceOf :: Eq a => [a] -> [a] -> Bool

Hi! There is a problem in a function, if we eval isSubsequenceOf "bl" "baaal" it would return True.

I've solve this task like this:

isSubsequenceOf :: Eq a => [a] -> [a] -> Bool
isSubsequenceOf xs ys = go xs ys
    where
        go [] _          = True
        go _ []          = False
        go (a:as) (b:bs) = (a == b && go as bs) || go xs bs

So I haven't found usage for xs@(x:_) syntax in this task:(

[dwayne]

@Bassov You're right. The s in my solution doesn't capture the original string at all times. Thanks for the contribution.