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|
-- |
-- Module : Unicode.Char.Case.Compat
-- Copyright : (c) 2020 Composewell Technologies and Contributors
-- License : Apache-2.0
-- Maintainer : streamly@composewell.com
-- Stability : experimental
--
-- Compatibility module for case and case mapping related functions.
--
-- The functions of this module are drop-in replacement for those in "Data.Char".
-- They are similar but not identical to some functions in "Unicode.Char.Case",
-- therefore they are placed in a separate module in order to avoid ambiguity.
--
module Unicode.Char.Case.Compat
( -- * Predicates
isUpper
, isLower
-- * Case conversion
, toUpper
, toLower
, toTitle
) where
import Unicode.Char.General (GeneralCategory(..), generalCategory)
import qualified Unicode.Internal.Char.UnicodeData.SimpleLowerCaseMapping as C
import qualified Unicode.Internal.Char.UnicodeData.SimpleTitleCaseMapping as C
import qualified Unicode.Internal.Char.UnicodeData.SimpleUpperCaseMapping as C
-- | Selects upper-case or title-case alphabetic Unicode characters (letters).
-- Title case is used by a small number of letter ligatures like the
-- single-character form of /Lj/.
--
-- It matches characters with general category 'UppercaseLetter' and
-- 'TitlecaseLetter'.
--
-- See: 'Unicode.Char.Case.isUpperCase' for the /full upper/ case predicate.
--
-- prop> isUpper c == Data.Char.isUpper c
--
-- @since 0.3.0
isUpper :: Char -> Bool
isUpper c = case generalCategory c of
UppercaseLetter -> True
TitlecaseLetter -> True
_ -> False
-- | Selects lower-case alphabetic Unicode characters (letters).
--
-- It matches characters with general category 'LowercaseLetter'.
--
-- See: 'Unicode.Char.Case.isLowerCase' for the /full/ lower case predicate.
--
-- prop> isLower c == Data.Char.isLower c
--
-- @since 0.3.0
isLower :: Char -> Bool
isLower c = case generalCategory c of
LowercaseLetter -> True
_ -> False
-- | Convert a letter to the corresponding upper-case letter, if any.
-- Any other character is returned unchanged.
--
-- It uses the character property @Simple_Uppercase_Mapping@.
--
-- See: 'Unicode.Char.Case.upperCaseMapping' and
-- 'Unicode.Char.Case.toUpperString' for /full/ upper case conversion.
--
-- prop> toUpper c == Data.Char.toUpper c
--
-- @since 0.3.0
{-# INLINE toUpper #-}
toUpper :: Char -> Char
toUpper = C.toSimpleUpperCase
-- | Convert a letter to the corresponding lower-case letter, if any.
-- Any other character is returned unchanged.
--
-- It uses the character property @Simple_Lowercase_Mapping@.
--
-- See: 'Unicode.Char.Case.lowerCaseMapping' and
-- 'Unicode.Char.Case.toLowerString' for /full/ lower case conversion.
--
-- prop> toLower c == Data.Char.toLower c
--
-- @since 0.3.0
{-# INLINE toLower #-}
toLower :: Char -> Char
toLower = C.toSimpleLowerCase
-- | Convert a letter to the corresponding title-case or upper-case letter,
-- if any. (Title case differs from upper case only for a small number of
-- ligature letters.) Any other character is returned unchanged.
--
-- It uses the character property @Simple_Titlecase_Mapping@.
--
-- See: 'Unicode.Char.Case.titleCaseMapping' and
-- 'Unicode.Char.Case.toTitleString' for /full/ title case conversion.
--
-- prop> toTitle c == Data.Char.toTitle c
--
-- @since 0.3.0
{-# INLINE toTitle #-}
toTitle :: Char -> Char
toTitle = C.toSimpleTitleCase
|
