#include "config.h"
-isAscii, isLatin1, isAsciiUpper, isAsciiLower :: Char -> Bool
+-- | Selects the first 128 characters of the Unicode character set,
+-- corresponding to the ASCII character set.
+isAscii :: Char -> Bool
isAscii c = c < '\x80'
+
+-- | Selects the first 256 characters of the Unicode character set,
+-- corresponding to the ISO 8859-1 (Latin-1) character set.
+isLatin1 :: Char -> Bool
isLatin1 c = c <= '\xff'
+
+isAsciiUpper, isAsciiLower :: Char -> Bool
isAsciiLower c = c >= 'a' && c <= 'z'
isAsciiUpper c = c >= 'A' && c <= 'Z'
-isControl, isPrint, isSpace, isUpper,
- isLower, isAlpha, isDigit, isOctDigit, isHexDigit, isAlphaNum
- :: Char -> Bool
+-- | Selects control characters, which are the non-printing characters of
+-- the Latin-1 subset of Unicode.
+isControl :: Char -> Bool
+
+-- | Selects printable Unicode characters
+-- (letters, numbers, marks, punctuation, symbols and spaces).
+isPrint :: Char -> Bool
+
+-- | Selects white-space characters in the Latin-1 range.
+-- (In Unicode terms, this includes spaces and some control characters.)
+isSpace :: Char -> Bool
+-- isSpace includes non-breaking space
+-- Done with explicit equalities both for efficiency, and to avoid a tiresome
+-- recursion with GHC.List elem
+isSpace c = c == ' ' ||
+ c == '\t' ||
+ c == '\n' ||
+ c == '\r' ||
+ c == '\f' ||
+ c == '\v' ||
+ c == '\xa0'
+
+-- | Selects alphabetic Unicode characters (letters) that are not lower-case.
+-- (In Unicode terms, this includes letters in upper and title cases,
+-- as well as modifier letters and other letters.)
+isUpper :: Char -> Bool
+
+-- | Selects lower-case alphabetic Unicode characters (letters).
+isLower :: Char -> Bool
+
+-- | Selects alphabetic Unicode characters (letters).
+isAlpha :: Char -> Bool
+-- | Selects alphabetic or numeric digit Unicode characters.
+--
+-- Note that numeric digits outside the ASCII range are selected by this
+-- function but not by 'isDigit'. Such digits may be part of identifiers
+-- but are not used by the printer and reader to represent numbers.
+isAlphaNum :: Char -> Bool
+
+-- | Selects ASCII digits, i.e. @\'0\'@..@\'9\'@.
+isDigit :: Char -> Bool
+
+-- | Selects ASCII octal digits, i.e. @\'0\'@..@\'7\'@.
+isOctDigit :: Char -> Bool
isOctDigit c = c >= '0' && c <= '7'
+
+-- | Selects ASCII hexadecimal digits,
+-- i.e. @\'0\'@..@\'9\'@, @\'a\'@..@\'f\'@, @\'A\'@..@\'F\'@.
+isHexDigit :: Char -> Bool
isHexDigit c = isDigit c || c >= 'A' && c <= 'F' ||
c >= 'a' && c <= 'f'
+-- | Convert a letter to the corresponding upper-case letter, leaving any
+-- other character unchanged. Any Unicode letter which has an upper-case
+-- equivalent is transformed.
+toUpper :: Char -> Char
+
+-- | Convert a letter to the corresponding lower-case letter, leaving any
+-- other character unchanged. Any Unicode letter which has a lower-case
+-- equivalent is transformed.
+toLower :: Char -> Char
+
-- -----------------------------------------------------------------------------
-- Win32 implementation
-#if defined(HAVE_WCTYPE_H) || mingw32_TARGET_OS
+#if (defined(HAVE_WCTYPE_H) && HAVE_ISWSPACE) || mingw32_TARGET_OS
-- Use the wide-char classification functions if available. Glibc
-- seems to implement these properly, even for chars > 0xffff, as long
isDigit c = iswdigit (fromIntegral (ord c)) /= 0
isAlpha c = iswalpha (fromIntegral (ord c)) /= 0
isAlphaNum c = iswalnum (fromIntegral (ord c)) /= 0
-isSpace c = iswspace (fromIntegral (ord c)) /= 0
+--isSpace c = iswspace (fromIntegral (ord c)) /= 0
isControl c = iswcntrl (fromIntegral (ord c)) /= 0
isPrint c = iswprint (fromIntegral (ord c)) /= 0
isUpper c = iswupper (fromIntegral (ord c)) /= 0
isControl c = c < ' ' || c >= '\DEL' && c <= '\x9f'
isPrint c = not (isControl c)
--- isSpace includes non-breaking space
--- Done with explicit equalities both for efficiency, and to avoid a tiresome
--- recursion with GHC.List elem
-isSpace c = c == ' ' ||
- c == '\t' ||
- c == '\n' ||
- c == '\r' ||
- c == '\f' ||
- c == '\v' ||
- c == '\xa0'
-
-- The upper case ISO characters have the multiplication sign dumped
-- randomly in the middle of the range. Go figure.
isUpper c = c >= 'A' && c <= 'Z' ||
-- Case-changing operations
-toUpper, toLower :: Char -> Char
toUpper c@(C## c##)
| isAsciiLower c = C## (chr## (ord## c## -## 32##))
| isAscii c = c
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