Reflection via codegen

// Having built-in JSON support is nice, but V also allows you to create efficient serializers for anything:
// TODO: not implemented yet
fn decode<T>(data string) T {
	mut result := T{}
	for field in T.fields {
		if field.typ == 'string' {
			result.$field = get_string(data, field.name)
		} else if field.typ == 'int' {
			result.$field = get_int(data, field.name)
		}
	}
	return result
}

// generates to:
fn decode_User(data string) User {
	mut result := User{}
	result.name = get_string(data, 'name')
	result.age = get_int(data, 'age')
	return result
}