regex: Unicode format escape

From: John Max Skaller (skaller_at_[hidden])
Date: 2001-06-23 09:57:39

Format strings allow

        \x{1A0]

as a unicode escape. The escapes

        \u01A0
        \U000001A0

are already available in strings for inserting ISO-10646/Unicode.
It isn't clear what happens with either code for strings
of 8 bit char :-)

Felix currently _requires_ conversion to UTF-8 for \uXXXX
escapes in 8 bit char strings (at lexing time). The double
escape for format strings:

        "\\x{1A0}"

leaves one wondering what bytes are generated.
Felix allows:

        \xXX
        \xXA

i.e., one hex digit or two. I do like the convention

        \x{XXXXXXXX}

though. However, I think it should generate a sequence of bytes,
and I think the number of X's should be required to be even.

It may be better to remove this notation temporarily,
so people don't use it and find the semantics are changed
by later Standardisation.

What happens for wchar_t?

-- 
John (Max) Skaller, mailto:skaller_at_[hidden]
10/1 Toxteth Rd Glebe NSW 2037 Australia voice: 61-2-9660-0850
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