simple_enum

enum_cast

Overview

The enum_cast function object facilitates compile-time or runtime conversion from std::string_view to enum values.

Error Handling

Upon encountering a string that doesn’t match any enumeration value, enum_cast_t yields a unexpected{enum_cast_error::invalid_cast}, signaling a conversion failure.

Interface Declaration

template<enum_concept enum_type>
struct enum_cast_t
{
    [[nodiscard]]
    constexpr auto operator()(std::string_view value) const noexcept
      -> expected<enum_type, enum_cast_error>;
};

template<enum_concept enum_type>
inline constexpr enum_cast_t<enum_type> enum_cast{};

• Parameters:
  • value: A std::string_view representing the name of the enumeration value.
• Returns:
  • A expected<enum_type, enum_cast_error> containing the corresponding enum value upon success or an error indicating an invalid cast upon failure.

Usage

Include the simple_enum/enum_cast.hpp in your project to use enum_cast.

To convert a std::string_view to an enum value, invoke enum_cast with the desired enum type and string. The operation returns an expected object that either holds the enum value or an error:

#include <simple_enum/enum_cast.hpp>

enum class my_enum { value1, value2, value3 };

// Define bounds for `my_enum`
consteval auto adl_enum_bounds(my_enum) -> simple_enum::adl_info<my_enum> {
    return {my_enum::value1, my_enum::value3};
}

// Convert string to `my_enum` value
auto result = enum_cast<my_enum>("value2");
if(result) {
    my_enum e = result.value();
    // Enum value successfully retrieved
} else {
    // Handle the invalid cast
}

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