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1576a578a0
* contrib library unused import removal * remove a few unused imports. * another round of unused import removal * another round of unused import deletion. * another round of unused import deletion.
105 lines
2.9 KiB
Idris
105 lines
2.9 KiB
Idris
module Data.String.Extra
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import Data.Nat
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import Data.String
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%default total
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infixl 5 +>
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infixr 5 <+
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||| Adds a character to the end of the specified string.
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|||
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||| ```idris example
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||| strSnoc "AB" 'C'
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||| ```
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||| ```idris example
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||| strSnoc "" 'A'
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||| ```
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public export
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strSnoc : String -> Char -> String
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strSnoc s c = s ++ (singleton c)
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||| Alias of `strSnoc`
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|||
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||| ```idris example
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||| "AB" +> 'C'
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||| ```
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public export
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(+>) : String -> Char -> String
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(+>) = strSnoc
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||| Alias of `strCons`
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|||
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||| ```idris example
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||| 'A' <+ "AB"
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||| ```
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public export
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(<+) : Char -> String -> String
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(<+) = strCons
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||| Take the first `n` characters from a string. Returns the whole string
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||| if it's too short.
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public export
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take : (n : Nat) -> (input : String) -> String
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take n str = substr Z n str
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||| Take the last `n` characters from a string. Returns the whole string
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||| if it's too short.
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public export
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takeLast : (n : Nat) -> (input : String) -> String
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takeLast n str with (length str)
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takeLast n str | len with (isLTE n len)
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takeLast n str | len | Yes prf = substr (len `minus` n) len str
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takeLast n str | len | No contra = str
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||| Remove the first `n` characters from a string. Returns the empty string if
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||| the input string is too short.
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public export
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drop : (n : Nat) -> (input : String) -> String
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drop n str = substr n (length str) str
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||| Remove the last `n` characters from a string. Returns the empty string if
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||| the input string is too short.
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public export
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dropLast : (n : Nat) -> (input : String) -> String
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dropLast n str = reverse (drop n (reverse str))
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||| Remove the first and last `n` characters from a string. Returns the empty
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||| string if the input string is too short.
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public export
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shrink : (n : Nat) -> (input : String) -> String
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shrink n str = dropLast n (drop n str)
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||| Concatenate the strings from a `Foldable` containing strings, separated by
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||| the given string.
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public export
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join : (sep : String) -> Foldable t => (xs : t String) -> String
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join sep xs = drop (length sep)
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(foldl (\acc, x => acc ++ sep ++ x) "" xs)
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||| Get a character from a string if the string is long enough.
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public export
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index : (n : Nat) -> (input : String) -> Maybe Char
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index n str with (unpack str)
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index n str | [] = Nothing
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index Z str | (x :: xs) = Just x
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index (S n) str | (x :: xs) = index n str | xs
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||| Indent each line of a given string by `n` spaces.
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public export
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indentLines : (n : Nat) -> String -> String
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indentLines n str = unlines $ map (indent n) $ lines str
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||| Left-justify a string to the given length, using the
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||| specified fill character on the right.
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export
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justifyLeft : Nat -> Char -> String -> String
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justifyLeft n c s = s ++ replicate (n `minus` length s) c
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||| Right-justify a string to the given length, using the
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||| specified fill character on the left.
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export
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justifyRight : Nat -> Char -> String -> String
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justifyRight n c s = replicate (n `minus` length s) c ++ s
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