module String where
{-| A built-in representation for efficient string manipulation. String literals
are enclosed in `"double quotes"`. Strings are *not* lists of characters.
# Basics
@docs isEmpty, length, reverse, repeat
# Building and Splitting
@docs cons, uncons, fromChar, append, concat, split, join, words, lines
# Get Substrings
@docs slice, left, right, dropLeft, dropRight
# Check for Substrings
@docs contains, startsWith, endsWith, indexes, indices
# Conversions
@docs toInt, toFloat, toList, fromList
# Formatting
Cosmetic operations such as padding with extra characters or trimming whitespace.
@docs toUpper, toLower,
pad, padLeft, padRight,
trim, trimLeft, trimRight
# Higher-Order Functions
@docs map, filter, foldl, foldr, any, all
-}
import Native.String
import Char
import Maybe (Maybe)
import Result (Result)
{-| Determine if a string is empty.
isEmpty "" == True
isEmpty "the world" == False
-}
isEmpty : String -> Bool
isEmpty = Native.String.isEmpty
{-| Add a character to the beginning of a string. -}
cons : Char -> String -> String
cons = Native.String.cons
{-| Create a string from a given character.
fromChar 'a' == "a"
-}
fromChar : Char -> String
fromChar char =
cons char ""
{-| Split a non-empty string into its head and tail. This lets you
pattern match on strings exactly as you would with lists.
uncons "abc" == Just ('a',"bc")
uncons "" == Nothing
-}
uncons : String -> Maybe (Char, String)
uncons = Native.String.uncons
{-| Append two strings. You can also use [the `(++)` operator](Basics#++)
to do this.
append "butter" "fly" == "butterfly"
-}
append : String -> String -> String
append = Native.String.append
{-| Concatenate many strings into one.
concat ["never","the","less"] == "nevertheless"
-}
concat : List String -> String
concat = Native.String.concat
{-| Get the length of a string.
length "innumerable" == 11
length "" == 0
-}
length : String -> Int
length = Native.String.length
{-| Transform every character in a string
map (\c -> if c == '/' then '.' else c) "a/b/c" == "a.b.c"
-}
map : (Char -> Char) -> String -> String
map = Native.String.map
{-| Keep only the characters that satisfy the predicate.
filter isDigit "R2-D2" == "22"
-}
filter : (Char -> Bool) -> String -> String
filter = Native.String.filter
{-| Reverse a string.
reverse "stressed" == "desserts"
-}
reverse : String -> String
reverse = Native.String.reverse
{-| Reduce a string from the left.
foldl cons "" "time" == "emit"
-}
foldl : (Char -> b -> b) -> b -> String -> b
foldl = Native.String.foldl
{-| Reduce a string from the right.
foldr cons "" "time" == "time"
-}
foldr : (Char -> b -> b) -> b -> String -> b
foldr = Native.String.foldr
{-| Split a string using a given separator.
split "," "cat,dog,cow" == ["cat","dog","cow"]
split "/" "home/evan/Desktop/" == ["home","evan","Desktop", ""]
Use `Regex.split` if you need something more flexible.
-}
split : String -> String -> List String
split = Native.String.split
{-| Put many strings together with a given separator.
join "a" ["H","w","ii","n"] == "Hawaiian"
join " " ["cat","dog","cow"] == "cat dog cow"
join "/" ["home","evan","Desktop"] == "home/evan/Desktop"
-}
join : String -> List String -> String
join = Native.String.join
{-| Repeat a string *n* times.
repeat 3 "ha" == "hahaha"
-}
repeat : Int -> String -> String
repeat = Native.String.repeat
{-| Take a substring given a start and end index. Negative indexes
are taken starting from the *end* of the list.
slice 7 9 "snakes on a plane!" == "on"
slice 0 6 "snakes on a plane!" == "snakes"
slice 0 -7 "snakes on a plane!" == "snakes on a"
slice -6 -1 "snakes on a plane!" == "plane"
-}
slice : Int -> Int -> String -> String
slice = Native.String.slice
{-| Take *n* characters from the left side of a string. -}
left : Int -> String -> String
left = Native.String.left
{-| Take *n* characters from the right side of a string. -}
right : Int -> String -> String
right = Native.String.right
{-| Drop *n* characters from the left side of a string. -}
dropLeft : Int -> String -> String
dropLeft = Native.String.dropLeft
{-| Drop *n* characters from the right side of a string. -}
dropRight : Int -> String -> String
dropRight = Native.String.dropRight
{-| Pad a string on both sides until it has a given length.
pad 5 ' ' "1" == " 1 "
pad 5 ' ' "11" == " 11 "
pad 5 ' ' "121" == " 121 "
-}
pad : Int -> Char -> String -> String
pad = Native.String.pad
{-| Pad a string on the left until it has a given length.
padLeft 5 '.' "1" == "....1"
padLeft 5 '.' "11" == "...11"
padLeft 5 '.' "121" == "..121"
-}
padLeft : Int -> Char -> String -> String
padLeft = Native.String.padLeft
{-| Pad a string on the right until it has a given length.
padRight 5 '.' "1" == "1...."
padRight 5 '.' "11" == "11..."
padRight 5 '.' "121" == "121.."
-}
padRight : Int -> Char -> String -> String
padRight = Native.String.padRight
{-| Get rid of whitespace on both sides of a string.
trim " hats \n" == "hats"
-}
trim : String -> String
trim = Native.String.trim
{-| Get rid of whitespace on the left of a string.
trimLeft " hats \n" == "hats \n"
-}
trimLeft : String -> String
trimLeft = Native.String.trimLeft
{-| Get rid of whitespace on the right of a string.
trimRight " hats \n" == " hats"
-}
trimRight : String -> String
trimRight = Native.String.trimRight
{-| Break a string into words, splitting on chunks of whitespace.
words "How are \t you? \n Good?" == ["How","are","you?","Good?"]
-}
words : String -> List String
words = Native.String.words
{-| Break a string into lines, splitting on newlines.
lines "How are you?\nGood?" == ["How are you?", "Good?"]
-}
lines : String -> List String
lines = Native.String.lines
{-| Convert a string to all upper case. Useful for case insensitive comparisons
and VIRTUAL YELLING.
-}
toUpper : String -> String
toUpper = Native.String.toUpper
{-| Convert a string to all lower case. Useful for case insensitive comparisons. -}
toLower : String -> String
toLower = Native.String.toLower
{-| Determine whether *any* characters satisfy a predicate.
any isDigit "90210" == True
any isDigit "R2-D2" == True
any isDigit "heart" == False
-}
any : (Char -> Bool) -> String -> Bool
any = Native.String.any
{-| Determine whether *all* characters satisfy a predicate.
all isDigit "90210" == True
all isDigit "R2-D2" == False
all isDigit "heart" == False
-}
all : (Char -> Bool) -> String -> Bool
all = Native.String.all
{-| See if the second string contains the first one.
contains "the" "theory" == True
contains "hat" "theory" == False
contains "THE" "theory" == False
Use `Regex.contains` if you need something more flexible.
-}
contains : String -> String -> Bool
contains = Native.String.contains
{-| See if the second string starts with the first one.
startsWith "the" "theory" == True
startsWith "ory" "theory" == False
-}
startsWith : String -> String -> Bool
startsWith = Native.String.startsWith
{-| See if the second string ends with the first one.
endsWith "the" "theory" == False
endsWith "ory" "theory" == True
-}
endsWith : String -> String -> Bool
endsWith = Native.String.endsWith
{-| Get all of the indexes for a substring in another string.
indexes "i" "Mississippi" == [1,4,7,10]
indexes "ss" "Mississippi" == [2,5]
indexes "needle" "haystack" == []
-}
indexes : String -> String -> List Int
indexes = Native.String.indexes
{-| Alias for `indexes` -}
indices : String -> String -> List Int
indices = Native.String.indexes
{-| Try to convert a string into an int, failing on improperly formatted strings.
toInt "123" == Ok 123
toInt "-42" == Ok -42
toInt "3.1" == Err "could not convert string '3.1' to an Int"
toInt "31a" == Err "could not convert string '31a' to an Int"
-}
toInt : String -> Result String Int
toInt = Native.String.toInt
{-| Try to convert a string into a float, failing on improperly formatted strings.
toFloat "123" == Ok 123.0
toFloat "-42" == Ok -42.0
toFloat "3.1" == Ok 3.1
toFloat "31a" == Err "could not convert string '31a' to a Float"
-}
toFloat : String -> Result String Float
toFloat = Native.String.toFloat
{-| Convert a string to a list of characters.
toList "abc" == ['a','b','c']
-}
toList : String -> List Char
toList = Native.String.toList
{-| Convert a list of characters into a String. Can be useful if you
want to create a string primarly by consing, perhaps for decoding
something.
fromList ['a','b','c'] == "abc"
-}
fromList : List Char -> String
fromList = Native.String.fromList