-----------------------------------------------------------------------------
-- |
-- Module      :  Data.Char
-- Copyright   :  (c) 2020-2021 EMQ Technologies Co., Ltd.
-- License     :  BSD-style (see the LICENSE file)
--
-- Maintainer  :  Feng Lee, feng@emqx.io
--                Yang M, yangm@emqx.io
-- Stability   :  experimental
-- Portability :  portable
--
-- The Unicode Char datatype.
--
-----------------------------------------------------------------------------
module Data.Char where

-----------------------------------------------------------------------------
-- | Character classification

-- | Unicode control characters: 0..31, 127.
foreign import isControl :: Char -> Boolean

-- | Unicode space characters:
-- ' '  (0x20) space (SPC)
-- '\t' (0x09) horizontal tab (TAB)
-- '\n' (0x0a) newline (LF)
-- '\v' (0x0b) vertical tab (VT)
-- '\f' (0x0c) feed (FF)
-- '\r' (0x0d) carriage return (CR)
foreign import isSpace :: Char -> Boolean

-- | Return true for a lowercase Unicode character.
foreign import isLower :: Char -> Boolean

-- | Return true for a uppercase Unicode character.
foreign import isUpper :: Char -> Boolean

-- | Alphabetic Unicode characters.
foreign import isAlpha :: Char -> Boolean

-- | Alphabetic or numeric Unicode characters.
foreign import isAlphaNum :: Char -> Boolean

-- | Printable characters.
foreign import isPrint :: Char -> Boolean

-- | ASCII digits: '0'..'9'.
foreign import isDigit :: Char -> Boolean

-- | ASCII octal digits: '0'..'7'.
foreign import isOctDigit :: Char -> Boolean

-- | ASCII hexadecimal digits: '0'..'9', 'a'..'f', 'A'..'F'.
foreign import isHexDigit :: Char -> Boolean

-- TODO: right?
isLetter :: Char -> Boolean
isLetter = isAlpha

-- | ASCII characters.
foreign import isAscii :: Char -> Boolean

-----------------------------------------------------------------------------
-- | Case conversion

-- | Converts a unicode character to its uppercase equivalent.
foreign import toUpper :: Char -> Char

-- | Converts a unicode character to its lowercase equivalent.
foreign import toLower :: Char -> Char

-- | Converts a unicode character to its titlecase or uppercase equivalent.
foreign import toTitle :: Char -> Char

-----------------------------------------------------------------------------
-- | Int conversion

-- | Convert a digit Char to the corresponding Int.
foreign import digitToInt :: Char -> Integer

-- | Convert an Int in the range 0..15 to the corresponding digit Char.
foreign import intToDigit :: Integer -> Char

foreign import ord :: Char -> Integer

foreign import chr :: Integer -> Char