《Haskell 2010语言报告》指出:
Haskell使用Unicode [2]字符集。然而,源程序目前偏向于早期版本Haskell所使用的ASCII字符集。
这是否意味着UTF-8?
在ghc-7.0.4/compiler/parser/Lexer.x.source中:
$unispace = \x05 -- Trick Alex into handling Unicode. See alexGetChar.
$whitechar = [\ \n\r\f\v $unispace]
$white_no_nl = $whitechar # \n
$tab = \t
$ascdigit = 0-9
$unidigit = \x03 -- Trick Alex into handling Unicode. See alexGetChar.
$decdigit = $ascdigit -- for now, should really be $digit (ToDo)
$digit = [$ascdigit $unidigit]
$special = [\(\)\,\;\[\]\`\{\}]
$ascsymbol = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~]
$unisymbol = \x04 -- Trick Alex into handling Unicode. See alexGetChar.
$symbol = [$ascsymbol $unisymbol] # [$special \_\:\"\']
$unilarge = \x01 -- Trick Alex into handling Unicode. See alexGetChar.
$asclarge = [A-Z]
$large = [$asclarge $unilarge]
$unismall = \x02 -- Trick Alex into handling Unicode. See alexGetChar.
$ascsmall = [a-z]
$small = [$ascsmall $unismall \_]
$unigraphic = \x06 -- Trick Alex into handling Unicode. See alexGetChar.
$graphic = [$small $large $symbol $digit $special $unigraphic \:\"\']
我不确定如何处理这个问题。alexGetChar
并没有提供太多帮助。