haskus-utils-compat-1.1: Compatibility modules with other external packages (ByteString, etc.)

Description

Wrap Data.Text

We plan to replace it with Haskus.Text in the future

Synopsis

# Documentation

data Text #

A space efficient, packed, unboxed Unicode text type.

Instances
 Instance detailsDefined in Data.Hashable.Class MethodshashWithSalt :: Int -> Text -> Int #hash :: Text -> Int # Instance detailsDefined in Formatting.Buildable Methods type Item Text Instance detailsDefined in Data.Text type Item Text = Char

copy :: Text -> Text #

O(n) Make a distinct copy of the given string, sharing no storage with the original string.

As an example, suppose you read a large string, of which you need only a small portion. If you do not use copy, the entire original array will be kept alive in memory by the smaller string. Making a copy "breaks the link" to the original array, allowing it to be garbage collected if there are no other live references to it.

O(n) Return the prefix of the second string if its suffix matches the entire first string.

Examples:

>>> stripSuffix "bar" "foobar"
Just "foo"

>>> stripSuffix ""    "baz"
Just "baz"

>>> stripSuffix "foo" "quux"
Nothing


This is particularly useful with the ViewPatterns extension to GHC, as follows:

{-# LANGUAGE ViewPatterns #-}
import Data.Text as T

quuxLength :: Text -> Int
quuxLength (stripSuffix "quux" -> Just pre) = T.length pre
quuxLength _                                = -1

commonPrefixes :: Text -> Text -> Maybe (Text, Text, Text) #

O(n) Find the longest non-empty common prefix of two strings and return it, along with the suffixes of each string at which they no longer match.

If the strings do not have a common prefix or either one is empty, this function returns Nothing.

Examples:

>>> commonPrefixes "foobar" "fooquux"
Just ("foo","bar","quux")

>>> commonPrefixes "veeble" "fetzer"
Nothing

>>> commonPrefixes "" "baz"
Nothing


O(n) Return the suffix of the second string if its prefix matches the entire first string.

Examples:

>>> stripPrefix "foo" "foobar"
Just "bar"

>>> stripPrefix ""    "baz"
Just "baz"

>>> stripPrefix "foo" "quux"
Nothing


This is particularly useful with the ViewPatterns extension to GHC, as follows:

{-# LANGUAGE ViewPatterns #-}
import Data.Text as T

fnordLength :: Text -> Int
fnordLength (stripPrefix "fnord" -> Just suf) = T.length suf
fnordLength _                                 = -1

isInfixOf :: Text -> Text -> Bool #

O(n+m) The isInfixOf function takes two Texts and returns True iff the first is contained, wholly and intact, anywhere within the second.

isSuffixOf :: Text -> Text -> Bool #

O(n) The isSuffixOf function takes two Texts and returns True iff the first is a suffix of the second.

isPrefixOf :: Text -> Text -> Bool #

O(n) The isPrefixOf function takes two Texts and returns True iff the first is a prefix of the second. Subject to fusion.

unwords :: [Text] -> Text #

O(n) Joins words using single space characters.

unlines :: [Text] -> Text #

O(n) Joins lines, after appending a terminating newline to each.

lines :: Text -> [Text] #

O(n) Breaks a Text up into a list of Texts at newline Chars. The resulting strings do not contain newlines.

words :: Text -> [Text] #

O(n) Breaks a Text up into a list of words, delimited by Chars representing white space.

zipWith :: (Char -> Char -> Char) -> Text -> Text -> Text #

O(n) zipWith generalises zip by zipping with the function given as the first argument, instead of a tupling function. Performs replacement on invalid scalar values.

zip :: Text -> Text -> [(Char, Char)] #

O(n) zip takes two Texts and returns a list of corresponding pairs of bytes. If one input Text is short, excess elements of the longer Text are discarded. This is equivalent to a pair of unpack operations.

count :: Text -> Text -> Int #

O(n+m) The count function returns the number of times the query string appears in the given Text. An empty query string is invalid, and will cause an error to be raised.

findIndex :: (Char -> Bool) -> Text -> Maybe Int #

O(n) The findIndex function takes a predicate and a Text and returns the index of the first element in the Text satisfying the predicate. Subject to fusion.

index :: Text -> Int -> Char #

O(n) Text index (subscript) operator, starting from 0.

Arguments

 :: Text needle to search for -> Text haystack in which to search -> [(Text, Text)]

O(n+m) Find all non-overlapping instances of needle in haystack. Each element of the returned list consists of a pair:

• The entire string prior to the kth match (i.e. the prefix)
• The kth match, followed by the remainder of the string

Examples:

>>> breakOnAll "::" ""
[]

>>> breakOnAll "/" "a/b/c/"
[("a","/b/c/"),("a/b","/c/"),("a/b/c","/")]


The needle parameter may not be empty.

breakOnEnd :: Text -> Text -> (Text, Text) #

O(n+m) Similar to breakOn, but searches from the end of the string.

The first element of the returned tuple is the prefix of haystack up to and including the last match of needle. The second is the remainder of haystack, following the match.

>>> breakOnEnd "::" "a::b::c"
("a::b::","c")


breakOn :: Text -> Text -> (Text, Text) #

O(n+m) Find the first instance of needle (which must be non-null) in haystack. The first element of the returned tuple is the prefix of haystack before needle is matched. The second is the remainder of haystack, starting with the match.

Examples:

>>> breakOn "::" "a::b::c"
("a","::b::c")

>>> breakOn "/" "foobar"
("foobar","")


Laws:

append prefix match == haystack
where (prefix, match) = breakOn needle haystack

If you need to break a string by a substring repeatedly (e.g. you want to break on every instance of a substring), use breakOnAll instead, as it has lower startup overhead.

filter :: (Char -> Bool) -> Text -> Text #

O(n) filter, applied to a predicate and a Text, returns a Text containing those characters that satisfy the predicate.

partition :: (Char -> Bool) -> Text -> (Text, Text) #

O(n) The partition function takes a predicate and a Text, and returns the pair of Texts with elements which do and do not satisfy the predicate, respectively; i.e.

partition p t == (filter p t, filter (not . p) t)

find :: (Char -> Bool) -> Text -> Maybe Char #

O(n) The find function takes a predicate and a Text, and returns the first element matching the predicate, or Nothing if there is no such element.

chunksOf :: Int -> Text -> [Text] #

O(n) Splits a Text into components of length k. The last element may be shorter than the other chunks, depending on the length of the input. Examples:

>>> chunksOf 3 "foobarbaz"
["foo","bar","baz"]

>>> chunksOf 4 "haskell.org"
["hask","ell.","org"]


split :: (Char -> Bool) -> Text -> [Text] #

O(n) Splits a Text 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.

>>> split (=='a') "aabbaca"
["","","bb","c",""]

>>> split (=='a') ""
[""]


Arguments

 :: Text String to split on. If this string is empty, an error will occur. -> Text Input text. -> [Text]

O(m+n) Break a Text into pieces separated by the first Text argument (which cannot be empty), consuming the delimiter. An empty delimiter is invalid, and will cause an error to be raised.

Examples:

>>> splitOn "\r\n" "a\r\nb\r\nd\r\ne"
["a","b","d","e"]

>>> splitOn "aaa"  "aaaXaaaXaaaXaaa"
["","X","X","X",""]

>>> splitOn "x"    "x"
["",""]


and

intercalate s . splitOn s         == id
splitOn (singleton c)             == split (==c)

(Note: the string s to split on above cannot be empty.)

tails :: Text -> [Text] #

O(n) Return all final segments of the given Text, longest first.

inits :: Text -> [Text] #

O(n) Return all initial segments of the given Text, shortest first.

group :: Text -> [Text] #

O(n) Group characters in a string by equality.

groupBy :: (Char -> Char -> Bool) -> Text -> [Text] #

O(n) Group characters in a string according to a predicate.

break :: (Char -> Bool) -> Text -> (Text, Text) #

O(n) break is like span, but the prefix returned is over elements that fail the predicate p.

span :: (Char -> Bool) -> Text -> (Text, Text) #

O(n) span, applied to a predicate p and text t, returns a pair whose first element is the longest prefix (possibly empty) of t of elements that satisfy p, and whose second is the remainder of the list.

splitAt :: Int -> Text -> (Text, Text) #

O(n) splitAt n t returns a pair whose first element is a prefix of t of length n, and whose second is the remainder of the string. It is equivalent to (take n t, drop n t).

strip :: Text -> Text #

O(n) Remove leading and trailing white space from a string. Equivalent to:

dropAround isSpace

O(n) Remove trailing white space from a string. Equivalent to:

dropWhileEnd isSpace

O(n) Remove leading white space from a string. Equivalent to:

dropWhile isSpace

dropAround :: (Char -> Bool) -> Text -> Text #

O(n) dropAround p t returns the substring remaining after dropping characters that satisfy the predicate p from both the beginning and end of t. Subject to fusion.

dropWhileEnd :: (Char -> Bool) -> Text -> Text #

O(n) dropWhileEnd p t returns the prefix remaining after dropping characters that satisfy the predicate p from the end of t. Subject to fusion.

Examples:

>>> dropWhileEnd (=='.') "foo..."
"foo"


dropWhile :: (Char -> Bool) -> Text -> Text #

O(n) dropWhile p t returns the suffix remaining after takeWhile p t. Subject to fusion.

takeWhileEnd :: (Char -> Bool) -> Text -> Text #

O(n) takeWhileEnd, applied to a predicate p and a Text, returns the longest suffix (possibly empty) of elements that satisfy p. Subject to fusion. Examples:

>>> takeWhileEnd (=='o') "foo"
"oo"


Since: text-1.2.2.0

takeWhile :: (Char -> Bool) -> Text -> Text #

O(n) takeWhile, applied to a predicate p and a Text, returns the longest prefix (possibly empty) of elements that satisfy p. Subject to fusion.

dropEnd :: Int -> Text -> Text #

O(n) dropEnd n t returns the prefix remaining after dropping n characters from the end of t.

Examples:

>>> dropEnd 3 "foobar"
"foo"


Since: text-1.1.1.0

drop :: Int -> Text -> Text #

O(n) drop n, applied to a Text, returns the suffix of the Text after the first n characters, or the empty Text if n is greater than the length of the Text. Subject to fusion.

takeEnd :: Int -> Text -> Text #

O(n) takeEnd n t returns the suffix remaining after taking n characters from the end of t.

Examples:

>>> takeEnd 3 "foobar"
"bar"


Since: text-1.1.1.0

take :: Int -> Text -> Text #

O(n) take n, applied to a Text, returns the prefix of the Text of length n, or the Text itself if n is greater than the length of the Text. Subject to fusion.

unfoldrN :: Int -> (a -> Maybe (Char, a)) -> a -> Text #

O(n) Like unfoldr, unfoldrN builds a Text from a seed value. However, the length of the result should be limited by the first argument to unfoldrN. This function is more efficient than unfoldr when the maximum length of the result is known and correct, otherwise its performance is similar to unfoldr. Subject to fusion. Performs replacement on invalid scalar values.

unfoldr :: (a -> Maybe (Char, a)) -> a -> Text #

O(n), where n is the length of the result. The unfoldr function is analogous to the List unfoldr. unfoldr builds a Text from a seed value. The function takes the element and returns Nothing if it is done producing the Text, otherwise Just (a,b). In this case, a is the next Char in the string, and b is the seed value for further production. Subject to fusion. Performs replacement on invalid scalar values.

replicate :: Int -> Text -> Text #

O(n*m) replicate n t is a Text consisting of the input t repeated n times.

mapAccumR :: (a -> Char -> (a, Char)) -> a -> Text -> (a, Text) #

The mapAccumR function behaves like a combination of map and a strict foldr; it applies a function to each element of a Text, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new Text. Performs replacement on invalid scalar values.

mapAccumL :: (a -> Char -> (a, Char)) -> a -> Text -> (a, Text) #

O(n) Like a combination of map and foldl'. Applies a function to each element of a Text, passing an accumulating parameter from left to right, and returns a final Text. Performs replacement on invalid scalar values.

scanr1 :: (Char -> Char -> Char) -> Text -> Text #

O(n) scanr1 is a variant of scanr that has no starting value argument. Subject to fusion. Performs replacement on invalid scalar values.

scanr :: (Char -> Char -> Char) -> Char -> Text -> Text #

O(n) scanr is the right-to-left dual of scanl. Performs replacement on invalid scalar values.

scanr f v == reverse . scanl (flip f) v . reverse

scanl1 :: (Char -> Char -> Char) -> Text -> Text #

O(n) scanl1 is a variant of scanl that has no starting value argument. Subject to fusion. Performs replacement on invalid scalar values.

scanl1 f [x1, x2, ...] == [x1, x1 f x2, ...]

scanl :: (Char -> Char -> Char) -> Char -> Text -> Text #

O(n) scanl is similar to foldl, but returns a list of successive reduced values from the left. Subject to fusion. Performs replacement on invalid scalar values.

scanl f z [x1, x2, ...] == [z, z f x1, (z f x1) f x2, ...]

Note that

last (scanl f z xs) == foldl f z xs.

minimum :: Text -> Char #

O(n) minimum returns the minimum value from a Text, which must be non-empty. Subject to fusion.

maximum :: Text -> Char #

O(n) maximum returns the maximum value from a Text, which must be non-empty. Subject to fusion.

all :: (Char -> Bool) -> Text -> Bool #

O(n) all p t determines whether all characters in the Text t satisfy the predicate p. Subject to fusion.

any :: (Char -> Bool) -> Text -> Bool #

O(n) any p t determines whether any character in the Text t satisfies the predicate p. Subject to fusion.

concatMap :: (Char -> Text) -> Text -> Text #

O(n) Map a function over a Text that results in a Text, and concatenate the results.

concat :: [Text] -> Text #

O(n) Concatenate a list of Texts.

foldr1 :: (Char -> Char -> Char) -> Text -> Char #

O(n) A variant of foldr that has no starting value argument, and thus must be applied to a non-empty Text. Subject to fusion.

foldr :: (Char -> a -> a) -> a -> Text -> a #

O(n) foldr, applied to a binary operator, a starting value (typically the right-identity of the operator), and a Text, reduces the Text using the binary operator, from right to left. Subject to fusion.

foldl1' :: (Char -> Char -> Char) -> Text -> Char #

O(n) A strict version of foldl1. Subject to fusion.

foldl1 :: (Char -> Char -> Char) -> Text -> Char #

O(n) A variant of foldl that has no starting value argument, and thus must be applied to a non-empty Text. Subject to fusion.

foldl' :: (a -> Char -> a) -> a -> Text -> a #

O(n) A strict version of foldl. Subject to fusion.

foldl :: (a -> Char -> a) -> a -> Text -> a #

O(n) foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a Text, reduces the Text using the binary operator, from left to right. Subject to fusion.

transpose :: [Text] -> [Text] #

O(n) The transpose function transposes the rows and columns of its Text argument. Note that this function uses pack, unpack, and the list version of transpose, and is thus not very efficient.

Examples:

>>> transpose ["green","orange"]
["go","rr","ea","en","ng","e"]

>>> transpose ["blue","red"]
["br","le","ud","e"]


justifyRight :: Int -> Char -> Text -> Text #

O(n) Right-justify a string to the given length, using the specified fill character on the left. Performs replacement on invalid scalar values.

Examples:

>>> justifyRight 7 'x' "bar"
"xxxxbar"

>>> justifyRight 3 'x' "foobar"
"foobar"


justifyLeft :: Int -> Char -> Text -> Text #

O(n) Left-justify a string to the given length, using the specified fill character on the right. Subject to fusion. Performs replacement on invalid scalar values.

Examples:

>>> justifyLeft 7 'x' "foo"
"fooxxxx"

>>> justifyLeft 3 'x' "foobar"
"foobar"


toTitle :: Text -> Text #

O(n) Convert a string to title case, using simple case conversion. Subject to fusion.

The first letter of the input is converted to title case, as is every subsequent letter that immediately follows a non-letter. Every letter that immediately follows another letter is converted to lower case.

The result string may be longer than the input string. For example, the Latin small ligature ﬂ (U+FB02) is converted to the sequence Latin capital letter F (U+0046) followed by Latin small letter l (U+006C).

Note: this function does not take language or culture specific rules into account. For instance, in English, different style guides disagree on whether the book name "The Hill of the Red Fox" is correctly title cased—but this function will capitalize every word.

Since: text-1.0.0.0

toUpper :: Text -> Text #

O(n) Convert a string to upper case, using simple case conversion. Subject to fusion.

The result string may be longer than the input string. For instance, the German "ß" (eszett, U+00DF) maps to the two-letter sequence "SS".

toLower :: Text -> Text #

O(n) Convert a string to lower case, using simple case conversion. Subject to fusion.

The result string may be longer than the input string. For instance, "İ" (Latin capital letter I with dot above, U+0130) maps to the sequence "i" (Latin small letter i, U+0069) followed by " ̇" (combining dot above, U+0307).

O(n) Convert a string to folded case. Subject to fusion.

This function is mainly useful for performing caseless (also known as case insensitive) string comparisons.

A string x is a caseless match for a string y if and only if:

toCaseFold x == toCaseFold y

The result string may be longer than the input string, and may differ from applying toLower to the input string. For instance, the Armenian small ligature "ﬓ" (men now, U+FB13) is case folded to the sequence "մ" (men, U+0574) followed by "ն" (now, U+0576), while the Greek "µ" (micro sign, U+00B5) is case folded to "μ" (small letter mu, U+03BC) instead of itself.

Arguments

 :: Text needle to search for. If this string is empty, an error will occur. -> Text replacement to replace needle with. -> Text haystack in which to search. -> Text

O(m+n) Replace every non-overlapping occurrence of needle in haystack with replacement.

This function behaves as though it was defined as follows:

replace needle replacement haystack =
intercalate replacement (splitOn needle haystack)


As this suggests, each occurrence is replaced exactly once. So if needle occurs in replacement, that occurrence will not itself be replaced recursively:

>>> replace "oo" "foo" "oo"
"foo"


In cases where several instances of needle overlap, only the first one will be replaced:

>>> replace "ofo" "bar" "ofofo"
"barfo"


reverse :: Text -> Text #

O(n) Reverse the characters of a string.

Example:

>>> T.reverse "desrever"
"reversed"


Subject to fusion.

intersperse :: Char -> Text -> Text #

O(n) The intersperse function takes a character and places it between the characters of a Text.

Example:

>>> T.intersperse '.' "SHIELD"
"S.H.I.E.L.D"


Subject to fusion. Performs replacement on invalid scalar values.

intercalate :: Text -> [Text] -> Text #

O(n) The intercalate function takes a Text and a list of Texts and concatenates the list after interspersing the first argument between each element of the list.

Example:

>>> T.intercalate "NI!" ["We", "seek", "the", "Holy", "Grail"]
"WeNI!seekNI!theNI!HolyNI!Grail"


map :: (Char -> Char) -> Text -> Text #

O(n) map f t is the Text obtained by applying f to each element of t.

Example:

>>> let message = pack "I am not angry. Not at all."
>>> T.map (\c -> if c == '.' then '!' else c) message
"I am not angry! Not at all!"


Subject to fusion. Performs replacement on invalid scalar values.

O(n) Compare the count of characters in a Text to a number. Subject to fusion.

This function gives the same answer as comparing against the result of length, but can short circuit if the count of characters is greater than the number, and hence be more efficient.

length :: Text -> Int #

O(n) Returns the number of characters in a Text. Subject to fusion.

null :: Text -> Bool #

O(1) Tests whether a Text is empty or not. Subject to fusion.

unsnoc :: Text -> Maybe (Text, Char) #

O(1) Returns all but the last character and the last character of a Text, or Nothing if empty.

Since: text-1.2.3.0

init :: Text -> Text #

O(1) Returns all but the last character of a Text, which must be non-empty. Subject to fusion.

tail :: Text -> Text #

O(1) Returns all characters after the head of a Text, which must be non-empty. Subject to fusion.

last :: Text -> Char #

O(1) Returns the last character of a Text, which must be non-empty. Subject to fusion.

uncons :: Text -> Maybe (Char, Text) #

O(1) Returns the first character and rest of a Text, or Nothing if empty. Subject to fusion.

head :: Text -> Char #

O(1) Returns the first character of a Text, which must be non-empty. Subject to fusion.

append :: Text -> Text -> Text #

O(n) Appends one Text to the other by copying both of them into a new Text. Subject to fusion.

snoc :: Text -> Char -> Text #

O(n) Adds a character to the end of a Text. This copies the entire array in the process, unless fused. Subject to fusion. Performs replacement on invalid scalar values.

cons :: Char -> Text -> Text infixr 5 #

O(n) Adds a character to the front of a Text. This function is more costly than its List counterpart because it requires copying a new array. Subject to fusion. Performs replacement on invalid scalar values.

pack :: String -> Text #

O(n) Convert a String into a Text. Subject to fusion. Performs replacement on invalid scalar values.

O(1) Convert a character into a Text. Subject to fusion. Performs replacement on invalid scalar values.

O(n) Convert a literal string into a Text. Subject to fusion.

This is exposed solely for people writing GHC rewrite rules.

Since: text-1.2.1.1

O(n) Convert a Text into a String. Subject to fusion.

O(1) The empty Text.

# Conversions

Decode Utf8

Encode Text into Utf8

Encode String into Utf8

# Formatting

textFormat :: Format Text a -> a Source #

Format a text (strict)

data Format r a #

A formatter. When you construct formatters the first type parameter, r, will remain polymorphic. The second type parameter, a, will change to reflect the types of the data that will be formatted. For example, in

myFormat :: Formatter r (Text -> Int -> r)
myFormat = "Person's name is " % text % ", age is " % hex


the first type parameter remains polymorphic, and the second type parameter is Text -> Int -> r, which indicates that it formats a Text and an Int.

When you run the Format, for example with format, you provide the arguments and they will be formatted into a string.

> format ("Person's name is " % text % ", age is " % hex) "Dave" 54
"Person's name is Dave, age is 36"

Instances
 Not particularly useful, but could be. Instance detailsDefined in Formatting.Internal Methodsfmap :: (a -> b) -> Format r a -> Format r b #(<\$) :: a -> Format r b -> Format r a # The same as (%). At present using Category has an import overhead, but one day it might be imported as standard. Instance detailsDefined in Formatting.Internal Methodsid :: Format a a #(.) :: Format b c -> Format a b -> Format a c # a ~ r => IsString (Format r a) Useful instance for writing format string. With this you can write Foo instead of now "Foo!". Instance detailsDefined in Formatting.Internal MethodsfromString :: String -> Format r a # Semigroup (Format r (a -> r)) Instance detailsDefined in Formatting.Internal Methods(<>) :: Format r (a -> r) -> Format r (a -> r) -> Format r (a -> r) #sconcat :: NonEmpty (Format r (a -> r)) -> Format r (a -> r) #stimes :: Integral b => b -> Format r (a -> r) -> Format r (a -> r) # Monoid (Format r (a -> r)) Useful instance for applying two formatters to the same input argument. For example: format (year <> "/" % month) now will yield "2015/01". Instance detailsDefined in Formatting.Internal Methodsmempty :: Format r (a -> r) #mappend :: Format r (a -> r) -> Format r (a -> r) -> Format r (a -> r) #mconcat :: [Format r (a -> r)] -> Format r (a -> r) #

(%) :: Format r a -> Format r' r -> Format r' a infixr 9 #

Concatenate two formatters.

formatter1 % formatter2 is a formatter that accepts arguments for formatter1 and formatter2 and concatenates their results. For example

format1 :: Format r (Text -> r)
format1 = "Person's name is " % text

format2 :: Format r r
format2 = ", "

format3 :: Format r (Int -> r)
format3 = "age is " % hex

myFormat :: Formatter r (Text -> Int -> r)
myFormat = format1 % format2 % format3


Notice how the argument types of format1 and format3 are gathered into the type of myFormat.

(This is actually the composition operator for Format's Category instance, but that is (at present) inconvenient to use with regular Prelude. So this function is provided as a convenience.)

(%.) :: Format r (Builder -> r') -> Format r' a -> Format r a infixr 8 #

Function compose two formatters. Will feed the result of one formatter into another.

# Parsing

Parse an hexadecimal number FIXME: use a real parser (MegaParsec, etc.)

# Get/Put

Put an UTF8 encoded text

Pull n bytes from the input, as a Buffer

Pull 0 terminal text

tshow :: Show a => a -> Text Source #

Show as Text

# IO

putStrLn :: Text -> IO () #

Write a string to stdout, followed by a newline.