Haskell 源编码

Question

Haskell 2010 语言报告说:

Haskell uses the Unicode [2] character set. However, source programs are currently biased toward the ASCII character set used in earlier versions of Haskell.

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 \:\"\']

...我不知道该怎么做。 alexGetChar真的没有帮助。

Answer 1

有a proposal将 UTF-8 标准化为 Haskell 源文件的标准编码，但我不确定它是否被接受。

在实践中，GHC 假定所有输入文件都是 UTF-8，但它会忽略注释中格式错误的字节序列。