[Haskell-cafe] Vertical tabs in source code and other obscure chars

[Brian Hulley]

Brian Hulley wrote:
> Hi,
> In the Haskell98 report at
> http://haskell.org/onlinereport/lexemes.html section 2.2 has the rule:
>
>    whitechar -> newline | vertab | space | tab | uniWhite
>
> Does anyone know what a vertical tab is supposed to do?
> Is there any reason to allow them as whitespace? (Does anyone in the
> universe actually use them?)

To rephrase my question, what is a Haskell lexer/parser supposed to do when 
it encounters a vertical tab? The description of the layout rule in the 
report does not specify what a vertical tab means.

If no-one knows the answer, perhaps the rule should be changed to:

    whitechar -> newline | space | tab | uniWhite

and a vertical tab's could just be treated as illegal characters.

Regards, Brian.
-- 
Logic empowers us and Love gives us purpose.
Yet still phantoms restless for eras long past,
congealed in the present in unthought forms,
strive mightily unseen to destroy us.

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