result of <T> {
	data:T,
	errors:error_list
}

result2 of <T> {
	data:T
	| errors:error_list
}

map of <T, K> {
	key:T,
	value:K,
	next:map of <T, K>?
}

f := (i:T, j:K) of <T, K> -> map of <T, K> {
	return @map of <T, K>
}

r1 = @result of <int>
r2 = @result2 of <int>
r3 = @result of <result of <int>>
r4 = f(3, 5.0) of <int, double>