Selects alphabetic Unicode characters (lower-case, upper-case and
title-case letters, plus letters of caseless scripts and modifiers
letters).
This function returns
True if its argument has one of the
following
GeneralCategorys, or
False otherwise:
- UppercaseLetter
- LowercaseLetter
- TitlecaseLetter
- ModifierLetter
- OtherLetter
Note: this function is
not equivalent to
isAlphabetic. See the description of
isAlphabetic for
further details.
isLetter c == Data.Char.isLetter c