On Wed, Aug 31, 2022 at 10:52:49AM -0400, Jason Merrill wrote:
> It could be more explicit, but I think we can assume that from the existing
> wording; it says it designates the named character. If there is no such
> character, that cannot be satisfied, so it must be ill-formed.
Ok.
> > So, we could reject the int h case above and accept silently the others?
>
> Why not warn on the others?
We were always silent for the cases like \u123X or \U12345X.
Do you think we should emit some warnings (but never pedwarns/errors in that
case) that it is universal character name like but not completely?
The following patch let's us silently accept:
#define z(x) 0
#define a z(
int b = a\u{});
int c = a\u{);
int d = a\N{});
int e = a\N{);
int f = a\u123);
int g = a\U1234567);
int h = a\N);
int i = a\NARG);
int j = a\N{abc});
int k = a\N{ABC.123});
The following 2 will be still rejected with errors:
int l = a\N{ABC});
int m = a\N{LATIN SMALL LETTER A WITH ACUTE});
the first one because ABC is not valid Unicode name and the latter because
it will be int m = aá); and will trigger other errors later.
Given what you said above, I think that is what we want for the last 2
for C++23, the question is if it is ok also for C++20/C17 etc. and whether
it should depend on -pedantic or -pedantic-errors or GNU vs. ISO mode
or not in that case. We could handle those 2 also differently, just
warn instead of error for the \N{ABC} case if not in C++23 mode when
identifier_pos.
--- libcpp/charset.cc.jj 2022-08-31 12:34:18.921176118 +0200
+++ libcpp/charset.cc 2022-08-31 16:50:48.862775486 +0200
@@ -1463,7 +1463,14 @@ _cpp_valid_ucn (cpp_reader *pfile, const
{
length = 4;
if (str == limit || *str != '{')
- cpp_error (pfile, CPP_DL_ERROR, "'\\N' not followed by '{'");
+ {
+ if (identifier_pos)
+ {
+ *cp = 0;
+ return false;
+ }
+ cpp_error (pfile, CPP_DL_ERROR, "'\\N' not followed by '{'");
+ }
else
{
str++;
@@ -1489,7 +1496,7 @@ _cpp_valid_ucn (cpp_reader *pfile, const
if (str < limit && *str == '}')
{
- if (name == str && identifier_pos)
+ if (identifier_pos && (name == str || !strict))
{
*cp = 0;
return false;
Jakub
