Re: C23 thoughts and opinions

On 14/06/2024 22:30, Keith Thompson wrote:

Now that it's too late to change the definition, I've thought of
something that I think would have been a better way to specify #embed.
 Define a new kind of string literal, with a "uc" prefix.  `uc"foo"` is
of type `unsigned char[3]`.  (Or `const unsigned char[3]`, if that's not
too radical.)  Unlike other string literals, there is no implicit
terminating '\0'.  Arbitrary byte values can of course be specified in
hexadecimal: uc"\x01\x02\x03\x04".  Since there's no terminating null
character and C doesn't support zero-sized objects, uc"" is a syntax
error.
 uc"..." string literals might be made even simpler, for example allowing
only hex digits and not requiring \x (uc"01020304" rather than
uc"\x01\x02\x03\x04").  That's probably overkill.  uc"..."  literals
could be useful in other contexts, and programmers will want
flexibility.  Maybe something like hex"01020304" (embedded spaces could
be ignored) could be defined in addition to uc"\x01\x02\x03\x04".

That's something I added to string literals in my language within the last few months. Nothing do with embedding (but it can make hex sequences within strings more efficient, if that approach was used).
Writing byte-at-a-time hex data was always a bit fiddly:
     0x12, 0x34, 0xAB, ...
     "\x12\x34\xAB...
It was made worse by my preference for `x` being in lower case, and the hex digits in upper case, otherwise 0XABC or 0Xab or 0xab look wrong.
What I did was create a new, variable-lenghth string escape sequence that looks like this:
   "ABC\h1234AB...\nopq"     // hex sequence between ABC & nopq
Hex digits after \h or \H are read in pairs. White space is allowed between pairs:
   "ABC\H 12 34 AB ...\nopq"
The only thing I wasn't sure about was the closing backslash, which looks at first like another escape code. But I think it is sound, although it can still be tweaked.