Accept simplistic IPv6 representations.

src/GenericParser/IPAddress.purs

@@ -1,7 +1,7 @@
 -- | `IPAddress` is a parser for internet protocol addresses (both IPv4 and IPv6).
 module GenericParser.IPAddress where
 
-import Prelude (bind, pure, ($), (<<<), (>), show, map)
+import Prelude (between, (||), bind, pure, ($), (<<<), (>), show, map)
 
 -- import Control.Alt ((<|>))
 -- import Control.Lazy (defer)
@@ -9,12 +9,45 @@ import Data.Array as A
 -- import Data.Either (Either(..))
 import Data.Maybe (Maybe(..))
 -- import Data.String as S
--- import Data.String.CodeUnits as CU
+import Data.String.CodeUnits as CU
 
 import GenericParser.Parser (Parser(..)
                             , failureError
                             , current_position
-                            , char, nat, eof)
+                            , tryMaybe
+                            , many1
+                            , sat, char, nat)
+
+data IPv6Error
+  = InvalidCharacter
+  | TooManyHexaDecimalCharacters
+
+isHexaDecimal :: Char -> Boolean
+isHexaDecimal c = between '0' '9' c || between 'a' 'f' c || between 'A' 'F' c
+
+hex :: forall e. Parser e Char
+hex = sat isHexaDecimal
+
+-- | `ipv6_chunk` analyses just a nibble 
+ipv6_chunk :: Parser IPv6Error String
+ipv6_chunk = do pos <- current_position
+                hexachars <- many1 hex
+                _ <- tryMaybe $ char ':'
+                if A.length hexachars > 4
+                then Parser \_ -> failureError pos (Just TooManyHexaDecimalCharacters)
+                else pure $ CU.fromCharArray hexachars
+
+-- | TODO: `ipv6` currently is oversimplistic and lacks shortened representation (with doubled ':' character).
+-- |
+-- | TODO: check for double ':'
+-- |
+-- | TODO: verify the number of chunks (groups of hexadecimal characters).
+-- |
+-- | TODO: accept IPv6 addresses between brackets ([ipv6]).
+ipv6 :: Parser IPv6Error String
+ipv6 = do chunks <- many1 ipv6_chunk
+          pure $ A.fold (A.intersperse ":" chunks)
+
 
 data IPv4Error
   = NumberTooBig Int
@@ -35,7 +68,6 @@ ipv4_generic4bytes =
      b3 <- ipv4_byte
      _ <- char '.'
      b4 <- ipv4_byte
-     _ <- eof
      pure $ A.fold (A.intersperse "." $ map show [b1,b2,b3,b4])
 
 ipv4 :: Parser IPv4Error String

test/Main.purs

@@ -41,6 +41,19 @@ test_series :: forall e v
   -> Effect Unit
 test_series l p v e a = foreachE a (\s -> logtest l p s v e)
 
+showerror_ipv6 :: IP.IPv6Error -> String
+showerror_ipv6 (IP.InvalidCharacter)             = "InvalidCharacter"
+showerror_ipv6 (IP.TooManyHexaDecimalCharacters) = "TooManyHexaDecimalCharacters"
+
+test_ipv6 :: String -> Effect Unit
+test_ipv6 ipv6string = do
+  log $ "(ipv6) parsing '" <> ipv6string <> "': "
+        <> case parse IP.ipv6 { string: ipv6string, position: 0 } of
+             Left { position, error } -> "failed at position " <> show position <> case error of
+               Nothing  -> " -> no error reported"
+               Just err -> " -> error: " <> showerror_ipv6 err
+             Right { suffix, result } -> "result: " <> result <> " '" <> suffix.string <> "'"
+
 showerror_ipv4 :: IP.IPv4Error -> String
 showerror_ipv4 (NumberTooBig x) = "value '" <> show x <> "' is > 255"
 
@@ -87,3 +100,7 @@ main = do
   test_ipv4 "1..2.3.4"
   test_ipv4 "1.5.10.255"
   test_ipv4 "100.200.300.400"
+
+  log ""
+  test_ipv6 "2001:0"
+  test_ipv6 "2001:0db8:0000:0000:0000:8a2e:0370:7334"