Contents

module Phone (number) where
import Data.Char (isDigit, isLetter)

number :: String -> Maybe String
number input
  | any isLetter input = Nothing
  | len == 10 = Just digits
  | len == 11 && head digits == '1' = Just $ tail digits
  | otherwise = Nothing
  where digits = filter isDigit input
        len = length digits

Version data entries

84 entries across 84 versions & 1 rubygems

Version	Path
trackler-2.1.0.11	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.10	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.9	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.8	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.7	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.6	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.5	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.4	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.3	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.2	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.1	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.1.0.0	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.55	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.54	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.53	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.52	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.51	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.50	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.49	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs
trackler-2.0.8.48	tracks/haskell/exercises/phone-number/examples/success-standard/src/Phone.hs