+{-# LANGUAGE FlexibleInstances #-}
+
-- | An IPv4 address pattern has four fields separated by ".". Each
-- field is either a decimal number, or a sequence inside "[]" that
-- contains one or more ";"-separated decimal numbers or
import Text.Read ( readMaybe )
+class Pretty a where
+ -- | Obtain a pretty 'String' representation of the given thingy.
+ prettyshow :: a -> String
+
+ -- | Pretty-print the given thingy.
+ pp :: a -> IO ()
+ pp = putStrLn . prettyshow
+
+
+-- | Define a 'Pretty' instance for the result of 'parse'. This lets
+-- us pretty-print the result of a parse attempt without worrying
+-- about whether or not it failed. If the parse failed, you get the
+-- same output that you usually would. Otherwise we pretty-print the
+-- parsed value.
+--
+instance Pretty a => Pretty (Either ParseError a) where
+ prettyshow (Left err) = show err
+ prettyshow (Right v) = prettyshow v
+
+
+-- * Octets
+
+-- | An ipv4 octet; that is, an integer between @0@ and @255@
+-- inclusive. This is the data type corresponding to a \"v4octet\"
+-- in the postscreen parser.
+--
newtype IPv4Octet = IPv4Octet Int
deriving (Eq, Show)
+
+instance Pretty IPv4Octet where
+ prettyshow (IPv4Octet x) = show x
+
+
+-- | Parse an IPv4 octet, which should contain a string of digits.
+-- Should fail if the parsed integer does not lie between @0@ and
+-- @255@ inclusive.
+--
+-- ==== _Examples_
+--
+-- Standard octets are parsed correctly:
+--
+-- >>> parseTest v4octet "0"
+-- IPv4Octet 0
+--
+-- >>> parseTest v4octet "127"
+-- IPv4Octet 127
+--
+-- >>> parseTest v4octet "255"
+-- IPv4Octet 255
+--
+-- Non-digit input throws an error:
+--
+-- >>> parseTest v4octet "Hello, World!"
+-- parse error at (line 1, column 1):
+-- unexpected "H"
+-- expecting digit
+--
+-- If we're given an integer outside the range @0..255@ (i.e. not a
+-- valid octet), we fail:
+--
+-- >>> parseTest v4octet "9000"
+-- parse error at (line 1, column 5):
+-- unexpected end of input
+-- expecting digit
+-- Octet "9000" must be between 0 and 255.
+--
+v4octet :: Parser IPv4Octet
+v4octet = do
+ s <- many1 digit
+ case ( readMaybe s :: Maybe Int ) of
+ -- If "many1 digit" gives us a list of digits, we should be able
+ -- to convert that to an Int! It will overflow rather than fail
+ -- if the input is too big/small, so it should really always
+ -- succeed.
+ Nothing -> unexpected "readMaybe failed on a sequence of digits!"
+
+ -- If we got an Int, make sure it's actually a representation of
+ -- an octet.
+ Just k -> if 0 <= k && k <= 255
+ then return (IPv4Octet k)
+ else fail ("Octet \"" ++ (show k)
+ ++ "\" must be between 0 and 255.")
+
+
+
+
+-- * Sequence members
+
+
+-- | An ipv4 \"sequence member\". A sequence member is either an
+-- integer (an octet) or a range of integers (contained in an
+-- octet). This data type corresponds to \"v4seq_member\" in the
+-- postscreen parser.
+--
data IPv4SequenceMember =
IPv4SequenceMemberOctet IPv4Octet
| IPv4SequenceMemberOctetRange IPv4Octet IPv4Octet
deriving (Eq, Show)
-data IPv4Sequence =
- IPv4SequenceSingleMember IPv4SequenceMember
- | IPv4SequenceOptions IPv4SequenceMember IPv4Sequence
- deriving (Eq, Show)
-
-data IPv4Field = IPv4FieldOctet IPv4Octet | IPv4FieldSequence IPv4Sequence
- deriving (Eq, Show)
-
-data IPv4Pattern =
- IPv4Pattern IPv4Field IPv4Field IPv4Field IPv4Field
- deriving (Eq, Show)
+instance Pretty IPv4SequenceMember where
+ prettyshow (IPv4SequenceMemberOctet octet) = prettyshow octet
+ prettyshow (IPv4SequenceMemberOctetRange octet1 octet2) =
+ (prettyshow octet1) ++ ".." ++ (prettyshow octet2)
-- | Parse an IPv4 \"sequence member\". A sequence member is either an
just_one = fmap IPv4SequenceMemberOctet v4octet
+
+-- * Sequences
+
+-- | An ipv4 \"sequence\". A sequence contains either a single
+-- \"sequence member\" (see 'IPv4SequenceMember'), or a sequence
+-- member along with another sequence. So, this is a potentially
+-- recursive definition. This type corresponds to \"v4sequence\" in
+-- the postscreen parser.
+--
+data IPv4Sequence =
+ IPv4SequenceSingleMember IPv4SequenceMember
+ | IPv4SequenceOptions IPv4SequenceMember IPv4Sequence
+ deriving (Eq, Show)
+
+
+instance Pretty IPv4Sequence where
+ prettyshow (IPv4SequenceSingleMember member) = prettyshow member
+ prettyshow (IPv4SequenceOptions member subsequence) =
+ (prettyshow member) ++ ";" ++ (prettyshow subsequence)
+
+
-- | Parse an IPv4 \"sequence\". A sequence is whatever is allowed
-- within square brackets. Basically it can be three things:
--
-- >>> parseTest v4sequence "1"
-- IPv4SequenceSingleMember (IPv4SequenceMemberOctet (IPv4Octet 1))
--
--- >>> parseTest v4sequence "1..2"
--- IPv4SequenceSingleMember (IPv4SequenceMemberOctetRange (IPv4Octet 1) (IPv4Octet 2))
+-- >>> pp $ parse v4sequence "" "1..2"
+-- 1..2
--
--- >>> parseTest v4sequence "1..2;8"
--- IPv4SequenceOptions (IPv4SequenceMemberOctetRange (IPv4Octet 1) (IPv4Octet 2)) (IPv4SequenceSingleMember (IPv4SequenceMemberOctet (IPv4Octet 8)))
+-- >>> pp $ parse v4sequence "" "1..2;8"
+-- 1..2;8
--
v4sequence :: Parser IPv4Sequence
v4sequence = try both <|> just_one -- Maybe sepBy is appropriate here?
just_one = fmap IPv4SequenceSingleMember v4seq_member
+
+-- * Fields
+
+data IPv4Field = IPv4FieldOctet IPv4Octet | IPv4FieldSequence IPv4Sequence
+ deriving (Eq, Show)
+
+
+instance Pretty IPv4Field where
+ prettyshow (IPv4FieldOctet octet) = prettyshow octet
+ prettyshow (IPv4FieldSequence seq) = "[" ++ (prettyshow seq) ++ "]"
+
+
-- | Parse an IPv4 \"field\", which is either a boring old octet, or a
-- 'v4sequence' within square brackets.
--
-- >>> parseTest v4field "127"
-- IPv4FieldOctet (IPv4Octet 127)
--
--- >>> parseTest v4field "[127]"
--- IPv4FieldSequence (IPv4SequenceSingleMember (IPv4SequenceMemberOctet (IPv4Octet 127)))
+-- >>> pp $ parse v4field "" "[127]"
+-- [127]
--
v4field :: Parser IPv4Field
v4field = just_octet <|> brackets
return $ IPv4FieldSequence s
--- | Parse an IPv4 octet, which should contain a string of digits.
--- Should fail if the parsed integer does not lie between @0@ and
--- @255@ inclusive.
---
--- ==== _Examples_
---
--- Standard octets are parsed correctly:
---
--- parseTest v4octet "0"
--- IPv4Octet 0
---
--- >>> parseTest v4octet "127"
--- IPv4Octet 127
---
--- >>> parseTest v4octet "255"
--- IPv4Octet 255
---
--- Non-digit input throws an error:
---
--- >>> parseTest v4octet "Hello, World!"
--- parse error at (line 1, column 1):
--- unexpected "H"
--- expecting digit
---
--- If we're given an integer outside the range @0..255@ (i.e. not a
--- valid octet), we fail:
---
--- >>> parseTest v4octet "9000"
--- parse error at (line 1, column 5):
--- unexpected end of input
--- expecting digit
--- Octet "9000" must be between 0 and 255.
---
-v4octet :: Parser IPv4Octet
-v4octet = do
- s <- many1 digit
- case ( readMaybe s :: Maybe Int ) of
- -- If "many1 digit" gives us a list of digits, we should be able
- -- to convert that to an Int! It will overflow rather than fail
- -- if the input is too big/small, so it should really always
- -- succeed.
- Nothing -> unexpected "readMaybe failed on a sequence of digits!"
- -- If we got an Int, make sure it's actually a representation of
- -- an octet.
- Just k -> if 0 <= k && k <= 255
- then return (IPv4Octet k)
- else fail ("Octet \"" ++ (show k)
- ++ "\" must be between 0 and 255.")
+-- * Patterns
+
+data IPv4Pattern =
+ IPv4Pattern IPv4Field IPv4Field IPv4Field IPv4Field
+ deriving (Eq, Show)
+
+
+instance Pretty IPv4Pattern where
+ prettyshow (IPv4Pattern f1 f2 f3 f4) =
+ (prettyshow f1) ++ "."
+ ++ (prettyshow f2)
+ ++ "."
+ ++ (prettyshow f3)
+ ++ "."
+ ++ (prettyshow f4)
-- | Parse an ipv4 address pattern. This consists of four fields,
--
-- ==== _Examples_
--
--- >>> parseTest v4pattern "127.0.0.1"
--- IPv4Pattern (IPv4FieldOctet (IPv4Octet 127)) (IPv4FieldOctet (IPv4Octet 0)) (IPv4FieldOctet (IPv4Octet 0)) (IPv4FieldOctet (IPv4Octet 1))
+-- >>> pp $ parse v4pattern "" "127.0.0.1"
+-- 127.0.0.1
+--
+-- >>> pp $ parse v4pattern "" "127.0.[1..3].1"
+-- 127.0.[1..3].1
+--
+-- >>> pp $ parse v4pattern "" "127.0.[1..3;8].1"
+-- 127.0.[1..3;8].1
+--
+-- In the module intro, it is mentioned that this is invalid:
+--
+-- >>> parseTest v4pattern "1.2.[3.4]"
+-- parse error at (line 1, column 7):
+-- unexpected "."
+-- expecting digit or "]"
+--
+-- This one is /also/ invalid; however, we'll parse the valid part off
+-- the front of it:
+--
+-- >>> pp $ parse v4pattern "" "1.2.3.3[6..9]"
+-- 1.2.3.3
--
v4pattern :: Parser IPv4Pattern
v4pattern = do
return $ IPv4Pattern field1 field2 field3 field4
+
+-- * Enumeration
+
-- | Enumerate the members of an 'IPv4SequenceMember'. A sequence
-- member is either an octet, which is easy to enumerate -- we just
-- print it -- or an octet range whose members can be enumerated
(sequence_members sm) ++ (sequences s)
+-- | Enumerate the members of an 'IPv4Field'. If the field contains a
+-- single 'IPv4Octet', we simply 'show' it. Otherwise it contains an
+-- 'IPv4FieldSequence', and we enumerate that recursively using
+-- 'sequences'.
+--
+-- ==== _Examples_
+--
+-- >>> let (Right r) = parse v4field "" "1"
+-- >>> fields r
+-- ["1"]
+--
+-- >>> let (Right r) = parse v4field "" "[127..135]"
+-- >>> fields r
+-- ["127","128","129","130","131","132","133","134","135"]
+--
fields :: IPv4Field -> [String]
fields (IPv4FieldOctet (IPv4Octet i)) = [show i]
fields (IPv4FieldSequence s) = sequences s
+-- | Enumerate the addresses represented by a given 'IPv4Pattern'.
+--
+-- A pattern contains four fields, sepearated by period
+-- characters. We want to list all possible combinations of
+-- addresses where the first octet comes from the first field, the
+-- second octet comes from the second field... and so on. To do
+-- this, we take advantage of the List monad and the fact that
+-- 'fields' returns a list of 'String's.
+--
+-- ==== _Examples_
+--
+-- A single address:
+--
+-- >>> let (Right r) = parse v4pattern "" "127.0.0.1"
+-- >>> addresses r
+-- ["127.0.0.1"]
+--
+-- Anything between 127.0.0.2 and 127.0.0.4, and either 127.0.0.10
+-- or 127.0.0.11:
+--
+-- >>> let (Right r) = parse v4pattern "" "127.0.0.[2..4;10;11]"
+-- >>> addresses r
+-- ["127.0.0.2","127.0.0.3","127.0.0.4","127.0.0.10","127.0.0.11"]
+--
addresses :: IPv4Pattern -> [String]
addresses (IPv4Pattern field1 field2 field3 field4) = do
f1 <- fields field1
return $ f1 ++ "." ++ f2 ++ "." ++ f3 ++ "." ++ f4
--- Tests
+
+-- * Tests
v4octet_tests :: TestTree
v4octet_tests =
projects / dead / harbl.git / commitdiff