struct FixedStruct1 {
    a int
    b string
    c ?int
    d ?string
}

struct Encoder {}

fn test_main() {
    fixed := FixedStruct1{123, '456', 789, '321'}
    assert fixed.a.str() == '123'
    assert fixed.b.int() == 456

    assert fixed.c?.str() == '789'
    assert fixed.d?.int() == 321

    e := Encoder{}
    e.encode_struct(fixed)
}

fn (e &Encoder) encode_struct[T](val T) {
    $for field in T.fields {
        $if !field.is_option {
            $if field.typ is int {
                assert val.$(field.name).str() == '123'
            } $else $if field.typ is string {
                assert val.$(field.name).int() == 456
            }
        } $else {
            $if field.typ is ?int {
                assert val.$(field.name) ?.str() == '789'
            } $else $if field.typ is ?string {
                assert val.$(field.name) ?.int() == 321
            }
        }
    }
}