[Haskell-cafe] Valid Haskell characters

Richard A. O'Keefe ok at cs.otago.ac.nz
Tue Aug 26 00:08:10 EDT 2008

On 26 Aug 2008, at 3:42 pm, Deborah Goldsmith wrote:

> All characters with general category Lu have the property Uppercase,  
> but the converse is not true.

It depends on what the OP wants to do with the information.
For example, Unicode Standard Annex 31,
is defined in terms of the General Character classification,
*not* in terms of the binary properties "Upper", "Alpha", &c.

When the Haskell report says
	uniSmall -> any Unicode lowercase letter
	uniLarge -> any uppercase or titlecase Unicode letter
it is really unclear what definition is meant: are we talking
about characters in general category Lu or Lt, or are we
talking about characters with the Uppercase property?
Since it's _identifiers_, I'd expect UAX#31 to apply, so it
should be general category.

The specification of the Char module is similarly ambiguous.
Since this is *not* about identifiers, I suppose this time
the Other_Uppercase characters might well be included.

It would be nice to have this spelled out clearly somewhere
not too far from the Report on haskell.org.

More information about the Haskell-Cafe mailing list