1 files changed, 5 insertions, 5 deletions

diff --git a/app/Data/Iban.hs b/app/Data/Iban.hs
index 45343ec..412577a 100644
--- a/app/Data/Iban.hs
+++ b/app/Data/Iban.hs
@@ -4,6 +4,8 @@ import Control.Applicative ((<|>))
 import Data.Attoparsec.Text as AP
 import Data.Char
   ( digitToInt,
+    isAscii,
+    isDigit,
     ord,
     toUpper,
   )
@@ -24,7 +26,7 @@ validateIban = AP.parseOnly $ do
     then
       if valid countryCode checkDigits chars
         then return ()
-        else fail $ "IBAN checksum does not match (" <> countryCode <> checkDigits <> chars <> ")"
+        else fail $ "IBAN checksum does not match (" ++ countryCode ++ checkDigits ++ chars ++ ")"
     else fail "IBAN has more than 34 characters"
   where
     letterToInt c = ord (toUpper c) - ord 'A' + 10
@@ -32,10 +34,8 @@ validateIban = AP.parseOnly $ do
       foldl'
         ( \acc -> \case
             d
-              | '0' <= d && d <= '9' -> acc * 10 + toInteger (digitToInt d)
-              | 'A' <= d && d <= 'Z'
-                  || 'a' <= d && d <= 'z' ->
-                  acc * 100 + toInteger (letterToInt d)
+              | isDigit d -> acc * 10 + toInteger (digitToInt d)
+              | isAscii d -> acc * 100 + toInteger (letterToInt d)
               | otherwise -> error "unreachable"
         )
         0