// An example deserializer implementation

struct User {
    name string
    age  int
}

fn main() {
    data := 'name=Alice\nage=18'
    user := decode[User](data)
    println(user)
}

fn decode[T](data string) T {
    mut result := T{}
    // compile-time `for` loop
    // T.fields gives an array of a field metadata type
    $for field in T.fields {
        $if field.typ is string {
            // $(string_expr) produces an identifier
            result.$(field.name) = get_string(data, field.name)
        } $else $if field.typ is int {
            result.$(field.name) = get_int(data, field.name)
        }
    }
    return result
}

fn get_string(data string, field_name string) string {
    for line in data.split_into_lines() {
        key_val := line.split('=')
        if key_val[0] == field_name {
            return key_val[1]
        }
    }
    return ''
}

fn get_int(data string, field string) int {
    return get_string(data, field).int()
}

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