The idea is to keep cake aligned with C, not a language fork.
But Cake itself could have a fork to Cake++. :D
Equally one which replaces 'auto' with the name of the type (and similar desugaring games) is still a C to C compiler, just running as a C23 to C99 or whatever. Resolve the branch in _Generic before emitting code as part of downgrading C11.
The lifetime annotations are an interesting one because they're a different language which, if it typechecks, can be losslessly converted into C (by dropping the annotations on the way out).
I'm not sure where in that design space the current implementation lies. In particular folding preprocessed code back into code that has the #defines and #includes in is a massive pain and only really valuable if you want to lean into the round trip capability.
Sample macro NEW using c23 typeof.
#include <stdlib.h>
#include <string.h>
static inline void* allocate_and_copy(void* s, size_t n) {
void* p = malloc(n);
if (p) {
memcpy(p, s, n);
}
return p;
}
#define NEW(...) (typeof(__VA_ARGS__)*) allocate_and_copy(&(__VA_ARGS__), sizeof(__VA_ARGS__))
#pragma expand NEW
struct X {
const int i;
};
int main() {
auto p = NEW((struct X) {});
}
#include <stdlib.h>
#include <string.h>
static inline void* allocate_and_copy(void* s, size_t n) {
void* p = malloc(n);
if (p) {
memcpy(p, s, n);
}
return p;
}
#define NEW(...) (typeof(__VA_ARGS__)*) allocate_and_copy(&(__VA_ARGS__), sizeof(__VA_ARGS__))
#pragma expand NEW
struct X {
const int i;
};
int main() {
struct X * p = (struct X*) allocate_and_copy(&((struct X) {0}), sizeof((struct X) {0}));
}