| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
System.OsString.Internal
Synopsis
- encodeUtf :: MonadThrow m => String -> m OsString
- unsafeEncodeUtf :: HasCallStack => String -> OsString
- encodeWith :: TextEncoding -> TextEncoding -> String -> Either EncodingException OsString
- encodeFS :: String -> IO OsString
- decodeUtf :: MonadThrow m => OsString -> m String
- decodeWith :: TextEncoding -> TextEncoding -> OsString -> Either EncodingException String
- decodeFS :: OsString -> IO String
- fromBytes :: MonadThrow m => ByteString -> m OsString
- osstr :: QuasiQuoter
- unpack :: OsString -> [OsChar]
- pack :: [OsChar] -> OsString
- empty :: OsString
- singleton :: OsChar -> OsString
- unsafeFromChar :: Char -> OsChar
- toChar :: OsChar -> Char
- snoc :: OsString -> OsChar -> OsString
- cons :: OsChar -> OsString -> OsString
- last :: HasCallStack => OsString -> OsChar
- tail :: HasCallStack => OsString -> OsString
- uncons :: OsString -> Maybe (OsChar, OsString)
- head :: HasCallStack => OsString -> OsChar
- init :: HasCallStack => OsString -> OsString
- unsnoc :: OsString -> Maybe (OsString, OsChar)
- null :: OsString -> Bool
- length :: OsString -> Int
- map :: (OsChar -> OsChar) -> OsString -> OsString
- reverse :: OsString -> OsString
- intercalate :: OsString -> [OsString] -> OsString
- foldl :: (a -> OsChar -> a) -> a -> OsString -> a
- foldl' :: (a -> OsChar -> a) -> a -> OsString -> a
- foldl1 :: (OsChar -> OsChar -> OsChar) -> OsString -> OsChar
- foldl1' :: (OsChar -> OsChar -> OsChar) -> OsString -> OsChar
- foldr :: (OsChar -> a -> a) -> a -> OsString -> a
- foldr' :: (OsChar -> a -> a) -> a -> OsString -> a
- foldr1 :: (OsChar -> OsChar -> OsChar) -> OsString -> OsChar
- foldr1' :: (OsChar -> OsChar -> OsChar) -> OsString -> OsChar
- all :: (OsChar -> Bool) -> OsString -> Bool
- any :: (OsChar -> Bool) -> OsString -> Bool
- concat :: [OsString] -> OsString
- replicate :: Int -> OsChar -> OsString
- unfoldr :: (a -> Maybe (OsChar, a)) -> a -> OsString
- unfoldrN :: Int -> (a -> Maybe (OsChar, a)) -> a -> (OsString, Maybe a)
- take :: Int -> OsString -> OsString
- takeEnd :: Int -> OsString -> OsString
- takeWhileEnd :: (OsChar -> Bool) -> OsString -> OsString
- takeWhile :: (OsChar -> Bool) -> OsString -> OsString
- drop :: Int -> OsString -> OsString
- dropEnd :: Int -> OsString -> OsString
- dropWhile :: (OsChar -> Bool) -> OsString -> OsString
- dropWhileEnd :: (OsChar -> Bool) -> OsString -> OsString
- breakEnd :: (OsChar -> Bool) -> OsString -> (OsString, OsString)
- break :: (OsChar -> Bool) -> OsString -> (OsString, OsString)
- span :: (OsChar -> Bool) -> OsString -> (OsString, OsString)
- spanEnd :: (OsChar -> Bool) -> OsString -> (OsString, OsString)
- splitAt :: Int -> OsString -> (OsString, OsString)
- split :: OsChar -> OsString -> [OsString]
- splitWith :: (OsChar -> Bool) -> OsString -> [OsString]
- stripSuffix :: OsString -> OsString -> Maybe OsString
- stripPrefix :: OsString -> OsString -> Maybe OsString
- isInfixOf :: OsString -> OsString -> Bool
- isPrefixOf :: OsString -> OsString -> Bool
- isSuffixOf :: OsString -> OsString -> Bool
- breakSubstring :: OsString -> OsString -> (OsString, OsString)
- elem :: OsChar -> OsString -> Bool
- find :: (OsChar -> Bool) -> OsString -> Maybe OsChar
- filter :: (OsChar -> Bool) -> OsString -> OsString
- partition :: (OsChar -> Bool) -> OsString -> (OsString, OsString)
- index :: HasCallStack => OsString -> Int -> OsChar
- indexMaybe :: OsString -> Int -> Maybe OsChar
- (!?) :: OsString -> Int -> Maybe OsChar
- elemIndex :: OsChar -> OsString -> Maybe Int
- elemIndices :: OsChar -> OsString -> [Int]
- count :: OsChar -> OsString -> Int
- findIndex :: (OsChar -> Bool) -> OsString -> Maybe Int
- findIndices :: (OsChar -> Bool) -> OsString -> [Int]
Documentation
encodeUtf :: MonadThrow m => String -> m OsString #
Partial unicode friendly encoding.
On windows this encodes as UTF16-LE (strictly), which is a pretty good guess. On unix this encodes as UTF8 (strictly), which is a good guess.
Throws an EncodingException if encoding fails. If the input does not
contain surrogate chars, you can use unsafeEncodeUtf.
unsafeEncodeUtf :: HasCallStack => String -> OsString #
Unsafe unicode friendly encoding.
Like encodeUtf, except it crashes when the input contains
surrogate chars. For sanitized input, this can be useful.
Arguments
| :: TextEncoding | unix text encoding |
| -> TextEncoding | windows text encoding |
| -> String | |
| -> Either EncodingException OsString |
Encode an OsString given the platform specific encodings.
encodeFS :: String -> IO OsString #
Like encodeUtf, except this mimics the behavior of the base library when doing filesystem
operations, which is:
- on unix, uses shady PEP 383 style encoding (based on the current locale, but PEP 383 only works properly on UTF-8 encodings, so good luck)
- on windows does permissive UTF-16 encoding, where coding errors generate Chars in the surrogate range
Looking up the locale requires IO. If you're not worried about calls
to setFileSystemEncoding, then unsafePerformIO may be feasible (make sure
to deeply evaluate the result to catch exceptions).
decodeUtf :: MonadThrow m => OsString -> m String #
Partial unicode friendly decoding.
On windows this decodes as UTF16-LE (strictly), which is a pretty good guess. On unix this decodes as UTF8 (strictly), which is a good guess. Note that filenames on unix are encoding agnostic char arrays.
Throws a EncodingException if decoding fails.
Arguments
| :: TextEncoding | unix text encoding |
| -> TextEncoding | windows text encoding |
| -> OsString | |
| -> Either EncodingException String |
Decode an OsString with the specified encoding.
The String is forced into memory to catch all exceptions.
decodeFS :: OsString -> IO String #
Like decodeUtf, except this mimics the behavior of the base library when doing filesystem
operations, which is:
- on unix, uses shady PEP 383 style encoding (based on the current locale, but PEP 383 only works properly on UTF-8 encodings, so good luck)
- on windows does permissive UTF-16 encoding, where coding errors generate Chars in the surrogate range
Looking up the locale requires IO. If you're not worried about calls
to setFileSystemEncoding, then unsafePerformIO may be feasible (make sure
to deeply evaluate the result to catch exceptions).
fromBytes :: MonadThrow m => ByteString -> m OsString #
Constructs an OsString from a ByteString.
On windows, this ensures valid UCS-2LE, on unix it is passed unchanged/unchecked.
Throws EncodingException on invalid UCS-2LE on windows (although unlikely).
osstr :: QuasiQuoter #
QuasiQuote an OsString. This accepts Unicode characters
and encodes as UTF-8 on unix and UTF-16 on windows.
If used as pattern, requires turning on the ViewPatterns extension.
pack :: [OsChar] -> OsString #
Pack a list of OsChar to an OsString
Note that using this in conjunction with unsafeFromChar to
convert from [Char] to OsString is probably not what
you want, because it will truncate unicode code points.
unsafeFromChar :: Char -> OsChar #
Truncates on unix to 1 and on Windows to 2 octets.
last :: HasCallStack => OsString -> OsChar #
O(1) Extract the last element of a OsString, which must be finite and non-empty. An exception will be thrown in the case of an empty OsString.
This is a partial function, consider using unsnoc instead.
Since: 1.4.200.0
tail :: HasCallStack => OsString -> OsString #
O(n) Extract the elements after the head of a OsString, which must be non-empty. An exception will be thrown in the case of an empty OsString.
This is a partial function, consider using uncons instead.
Since: 1.4.200.0
head :: HasCallStack => OsString -> OsChar #
O(1) Extract the first element of a OsString, which must be non-empty. An exception will be thrown in the case of an empty OsString.
This is a partial function, consider using uncons instead.
Since: 1.4.200.0
init :: HasCallStack => OsString -> OsString #
map :: (OsChar -> OsChar) -> OsString -> OsString #
O(n) map f xs is the OsString obtained by applying f to each
element of xs.
Since: 1.4.200.0
reverse :: OsString -> OsString #
O(n) reverse xs efficiently returns the elements of xs in reverse order.
Since: 1.4.200.0
intercalate :: OsString -> [OsString] -> OsString #
O(n) The intercalate function takes a OsString and a list of
OsStrings and concatenates the list after interspersing the first
argument between each element of the list.
Since: 1.4.200.0
foldl :: (a -> OsChar -> a) -> a -> OsString -> a #
foldl, applied to a binary operator, a starting value (typically
the left-identity of the operator), and a OsString, reduces the
OsString using the binary operator, from left to right.
Since: 1.4.200.0
foldr :: (OsChar -> a -> a) -> a -> OsString -> a #
foldr, applied to a binary operator, a starting value
(typically the right-identity of the operator), and a OsString,
reduces the OsString using the binary operator, from right to left.
Since: 1.4.200.0
replicate :: Int -> OsChar -> OsString #
O(n) replicate n x is a OsString of length n with x
the value of every element. The following holds:
replicate w c = unfoldr w (\u -> Just (u,u)) c
Since: 1.4.200.0
unfoldr :: (a -> Maybe (OsChar, a)) -> a -> OsString #
O(n), where n is the length of the result. The unfoldr
function is analogous to the List 'unfoldr'. unfoldr builds a
OsString from a seed value. The function takes the element and
returns Nothing if it is done producing the OsString or returns
Just (a,b), in which case, a is the next byte in the string,
and b is the seed value for further production.
This function is not efficient/safe. It will build a list of [Word8]
and run the generator until it returns Nothing, otherwise recurse infinitely,
then finally create a OsString.
If you know the maximum length, consider using unfoldrN.
Examples:
unfoldr (\x -> if x <= 5 then Just (x, x + 1) else Nothing) 0 == pack [0, 1, 2, 3, 4, 5]
Since: 1.4.200.0
unfoldrN :: Int -> (a -> Maybe (OsChar, a)) -> a -> (OsString, Maybe a) #
O(n) Like unfoldr, unfoldrN builds a OsString from a seed
value. However, the length of the result is limited by the first
argument to unfoldrN. This function is more efficient than unfoldr
when the maximum length of the result is known.
The following equation relates unfoldrN and unfoldr:
fst (unfoldrN n f s) == take n (unfoldr f s)
Since: 1.4.200.0
takeWhileEnd :: (OsChar -> Bool) -> OsString -> OsString #
Returns the longest (possibly empty) suffix of elements satisfying the predicate.
is equivalent to takeWhileEnd p.reverse . takeWhile p . reverse
Since: 1.4.200.0
takeWhile :: (OsChar -> Bool) -> OsString -> OsString #
Similar to takeWhile,
returns the longest (possibly empty) prefix of elements
satisfying the predicate.
Since: 1.4.200.0
dropWhile :: (OsChar -> Bool) -> OsString -> OsString #
Similar to dropWhile,
drops the longest (possibly empty) prefix of elements
satisfying the predicate and returns the remainder.
Since: 1.4.200.0
dropWhileEnd :: (OsChar -> Bool) -> OsString -> OsString #
Similar to dropWhileEnd,
drops the longest (possibly empty) suffix of elements
satisfying the predicate and returns the remainder.
is equivalent to dropWhileEnd p.reverse . dropWhile p . reverse
Since: 1.4.200.0
breakEnd :: (OsChar -> Bool) -> OsString -> (OsString, OsString) #
Returns the longest (possibly empty) suffix of elements which do not satisfy the predicate and the remainder of the string.
breakEnd p is equivalent to and to spanEnd (not . p)(.takeWhileEnd (not . p) &&& dropWhileEnd (not . p))
Since: 1.4.200.0
spanEnd :: (OsChar -> Bool) -> OsString -> (OsString, OsString) #
Returns the longest (possibly empty) suffix of elements satisfying the predicate and the remainder of the string.
spanEnd p is equivalent to and to breakEnd (not . p)(.takeWhileEnd p &&& dropWhileEnd p)
We have
spanEnd (not . isSpace) "x y z" == ("x y ", "z")and
spanEnd (not . isSpace) sbs == let (x, y) = span (not . isSpace) (reverse sbs) in (reverse y, reverse x)
Since: 1.4.200.0
split :: OsChar -> OsString -> [OsString] #
O(n) Break a OsString into pieces separated by the byte
argument, consuming the delimiter. I.e.
split 10 "a\nb\nd\ne" == ["a","b","d","e"] -- fromEnum '\n' == 10 split 97 "aXaXaXa" == ["","X","X","X",""] -- fromEnum 'a' == 97 split 120 "x" == ["",""] -- fromEnum 'x' == 120 split undefined "" == [] -- and not [""]
and
intercalate [c] . split c == id split == splitWith . (==)
Since: 1.4.200.0
splitWith :: (OsChar -> Bool) -> OsString -> [OsString] #
O(n) Splits a OsString into components delimited by
separators, where the predicate returns True for a separator element.
The resulting components do not contain the separators. Two adjacent
separators result in an empty component in the output. eg.
splitWith (==97) "aabbaca" == ["","","bb","c",""] -- fromEnum 'a' == 97 splitWith undefined "" == [] -- and not [""]
Since: 1.4.200.0
stripSuffix :: OsString -> OsString -> Maybe OsString #
O(n) The stripSuffix function takes two OsStrings and returns Just
the remainder of the second iff the first is its suffix, and otherwise
Nothing.
Since: 1.4.200.0
stripPrefix :: OsString -> OsString -> Maybe OsString #
O(n) The stripPrefix function takes two OsStrings and returns Just
the remainder of the second iff the first is its prefix, and otherwise
Nothing.
Since: 1.4.200.0
isInfixOf :: OsString -> OsString -> Bool #
Check whether one string is a substring of another.
Since: 1.4.200.0
isPrefixOf :: OsString -> OsString -> Bool #
O(n) The isPrefixOf function takes two OsStrings and returns True
Since: 1.4.200.0
isSuffixOf :: OsString -> OsString -> Bool #
O(n) The isSuffixOf function takes two OsStrings and returns True
iff the first is a suffix of the second.
The following holds:
isSuffixOf x y == reverse x `isPrefixOf` reverse y
Since: 1.4.200.0
breakSubstring :: OsString -> OsString -> (OsString, OsString) #
Break a string on a substring, returning a pair of the part of the string prior to the match, and the rest of the string.
The following relationships hold:
break (== c) l == breakSubstring (singleton c) l
For example, to tokenise a string, dropping delimiters:
tokenise x y = h : if null t then [] else tokenise x (drop (length x) t)
where (h,t) = breakSubstring x yTo skip to the first occurrence of a string:
snd (breakSubstring x y)
To take the parts of a string before a delimiter:
fst (breakSubstring x y)
Note that calling `breakSubstring x` does some preprocessing work, so you should avoid unnecessarily duplicating breakSubstring calls with the same pattern.
Since: 1.4.200.0
filter :: (OsChar -> Bool) -> OsString -> OsString #
O(n) filter, applied to a predicate and a OsString,
returns a OsString containing those characters that satisfy the
predicate.
Since: 1.4.200.0
partition :: (OsChar -> Bool) -> OsString -> (OsString, OsString) #
O(n) The partition function takes a predicate a OsString and returns
the pair of OsStrings with elements which do and do not satisfy the
predicate, respectively; i.e.,
partition p bs == (filter p sbs, filter (not . p) sbs)
Since: 1.4.200.0
index :: HasCallStack => OsString -> Int -> OsChar #
O(1) OsString index (subscript) operator, starting from 0.
Since: 1.4.200.0
elemIndices :: OsChar -> OsString -> [Int] #
O(n) The elemIndices function extends elemIndex, by returning
the indices of all elements equal to the query element, in ascending order.
Since: 1.4.200.0
count :: OsChar -> OsString -> Int #
count returns the number of times its argument appears in the OsString
Since: 1.4.200.0
findIndices :: (OsChar -> Bool) -> OsString -> [Int] #
O(n) The findIndices function extends findIndex, by returning the
indices of all elements satisfying the predicate, in ascending order.
Since: 1.4.200.0