v: refactor typeof(expr) feature [DRAFT]

[felipensp]

v: refactor typeof(expr) feature [DRAFT]

[felipensp]

@spytheman feel free to edit the FR with your suggestions.

[enghitalo]

What is the chance of have something like

struct TypeData {
...
nr_muls int
}

This can help to avoid need use

#ifdef __GNUC__
#define IS_POINTER(x) __builtin_types_compatible_p(__typeof__(x), void *)
#else
#define IS_POINTER(x) (((void*)(x) == (void*)0) != ((void*)&(x) == (void*)0))
#endif

To verify if it is pointer

[felipensp]

What is the chance of have something like

struct TypeData {
...
indirections int
}

This can help to avoid need use

#ifdef __GNUC__
#define IS_POINTER(x) __builtin_types_compatible_p(__typeof__(x), void *)
#else
#define IS_POINTER(x) (((void*)(x) == (void*)0) != ((void*)&(x) == (void*)0))
#endif

To verify if it is pointer

Yes, the indirectionsone from FieldData must be in the new TypeData and an is_ptr field too.

[enghitalo]

@felipensp Just for FieldData? I was thing in something like

fn main() {
	a := 'a'
	pa := &a
	ppa := &pa
	pppa := &ppa

	assert count_nr_muls(a) == 0
	assert count_nr_muls(pa) == 1
	assert count_nr_muls(ppa) == 2
	assert count_nr_muls(pppa) == 3
}

fn count_nr_muls[T](val T) int {
	return typeof[T]().nr_muls
}

[spytheman]

Use typeof[T](), not typeof(T) .

[enghitalo]

Use typeof[T](), not typeof(T) .

Please try again.](code.v:14:21: error: invalid field .nr_muls for type typeof[T]())