<b_jonas> slashlearn =@ccc/=@ccc is a great innovation in gcc 6, kept top secret, where inline asm statements can return a value in the carry flag on x86_64. See https://gcc.gnu.org/gcc-6/changes.html which keeps this secret, https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/Extended-Asm.html , http://article.gmane.org/gmane.linux.kernel/2238065 .

Augmented Backus-Naur Form, an update on the popular Backus-Naur Form programming language, introduces support for "Augmented Production", e.g. `foo +::= bar`. The older `::=` syntax will continue to be supported for orthogonal-compatibility purposes.