[M3devel] Widechars

[hendrik at topoi.pooq.com]

On Tue, Jan 06, 2009 at 09:25:08PM -0600, Rodney M. Bates wrote:
> Literals of type WIDECHAR are written, e.g. W'\x304A', note the 'W'.
> It makes them have type WIDECHAR and also enables the 16-bit escape
> sequences you are using.  If it is a CHAR or plain TEXT literal
> (no 'W' or 'w'), octal escapes must have exactly 3 octal digits and
> hex escapes must have exactly 2 hex digits.  In WIDECHAR and wide
> TEXT literals, octal escapes must have exactly 6 and hex escapes
> exactly 4.

I've always thought that octal and hexadecimal escapes should be 
self-delimiting.  In the process of moving from 8- to 16-bit characters, 
the length of the escapes has changed, and we're going to hit it again 
when we implement the larger-than-16-bit Unicode charaters.

In C, for strings, you can force early termination of an escape by 
ending the string with a quote, then a space, then starting a new string 
with another quote (since consecutive strings are implicitly 
concatenated, so you can write a really long string that doesn't fit on 
a line).  At least, that's what I seem to remember.  I haven't actually 
hacked this stuff for a long time.

> 
> Note that character literals without/with the 'W' are of different
> types, CHAR and WIDECHAR, respectively.  For Text literals, both
> forms have the same type TEXT, but the lexical formation rules
> are different without/with the 'W'.

Are we going to have to implement 'WW' to avoid retrocompatibility 
problems?

-- hendrik