/*
struct group {
	alts_tail: group_alt ptrdiff32
	alts_head: group_alt ptrdiff32
	up: group ptrdiff32
}

struct group_alt {
	text_tail: text_node ptrdiff32
	text_head: text_node ptrdiff32
	next: group_alt ptrdiff32
}

struct text_node {
	type: i32 enum {
		// null = 0
		murder = 1 // union: void[0]
		wiped = 2 // union: void[0]
		chars = 3 // union: text_chars
		group = 4 // union: group
	}
	next: text_node ptrdiff32
	data: union ...
}

struct text_chars {
	text: char[]rev ptrdiff32
	len: u32
}

struct parse_state {
	current_gr: group ptr64
	mother_gr: group ptr64
	regchar: char ptr64
	callback: fn ptr64
	cbdata: void ptr64
	...?
}
*/