requirements.md

Requirements are an abstraction that expresses the constraints imposed on a type or field. They affect schema generation, as well as validation during parsing/serialization.

In general, the entire system is designed in such a way as to support both requirements whose values are completely constexpr and those that are not.

Note that using constexpr requirements will allow the compiler to generate unique validation functions if it does not consider it necessary to inline the call, which in turn will reduce the number of unnecessary checks.

Array Requirements

Declaration of array_requirements

struct array_requirements {
    utils::ce::optional<std::size_t> min_items;
    utils::ce::optional<std::size_t> max_items;
    bool unique_items = false;
};

The fields correspond to the corresponding restrictions on values from OpenApi.

• min_items Minimum size of array(inclusive).
• max_items Maximum size of array(inclusive).
• unique_items Prohibit duplicate items

Number requirements

Declaration of number_requirements

template <typename T>
struct number_requirements {
    utils::ce::optional<T> minimum;
    utils::ce::optional<T> maximum;
    bool exclusive_minimum = false;
    bool exclusive_maximum = false;
    utils::ce::optional<T> multiple_of;
};

The fields correspond to the corresponding restrictions on values from OpenApi.

• minimum Minimum of value.
• maximum Maximum of value.
• exclusive_minimum Do not include the minimum in the acceptable range
• exclusive_maximum Do not include the maximum in the acceptable range
• multiple_of The value must be completely divisible by this number (the concept is completely applicable to fractional numbers, but they should be handled with extreme caution)

String requirements

Declaration of number_requirements

template <utils::ce::string Format = "">
struct string_requirements {
    utils::ce::optional<std::size_t> min_length;
    utils::ce::optional<std::size_t> max_length;
    utils::ce::string pattern;
    static constexpr auto format = Format;
};

• min_length Minimum length of string(exclusive)
• max_length Maximum length of string(exclusive)
• pattern The regular expression(ECMA standard) that the value must match
• Format The name of the format that the value should satisfy

Declaration of string_validator

template <utils::ce::string Format = "">
template <utils::ce::string Format>
struct string_validator {
    // must have static validate_result validate(std::string_view)
};

Declaration of noop validator

template <>
struct string_validator<""> {
    static validate_result validate(std::string_view) {
        return validate_result::ok();
    }
};

The format check is performed as follows: called string_validator<Format>::validate(str)

validate must return type which satisfy is_validate_result<T>

Supported formats:

• date-time