example.cpp

#include "include/meta_enum.hpp"
#include <iostream>

//helpers
constexpr int sum(int a, int b, int c)
{
    return a + b + c;
}

//can be used for global or nested enums or enum classes
//first arg is the name of the enum. second is the underlying type. The rest are enum members.

meta_enum(Global, int, GlobalA, GlobalB = 3, GlobalC, GlobalD = 100);
meta_enum_class(GlobalClass, uint8_t, GlobalClassA, GlobalClassB = 3, GlobalClassC);

struct Nester
{
    meta_enum(Nested, int, NestedA, NestedB = 3);
    meta_enum_class(NestedClass, uint8_t, NestedClassA = 3, NestedClassB = 1 >> 3);
};

//also works with very complexly defined enum entries
meta_enum(Complex, int, First, Second= sum(1, {(2, ")h(),,\"ej", 1)}, 4 >> 2), Third =     4,
Fourth);

//static assertions to verify that the complexly defined enum is parsed correctly
static_assert(Complex_meta.members.size() == 4);
static_assert(Complex_meta.members[0].string == "First");
static_assert(Complex_meta.members[1].string == " Second= sum(1, {(2, \")h(),,\\\"ej\", 1)}, 4 >> 2)");
static_assert(Complex_meta.members[2].string == " Third = 4");
static_assert(Complex_meta.members[3].string == " Fourth");

static_assert(Complex_meta.members[0].name == "First");
static_assert(Complex_meta.members[1].name == "Second");
static_assert(Complex_meta.members[2].name == "Third");
static_assert(Complex_meta.members[3].name == "Fourth");

static_assert(Complex_meta.members[0].value == 0);
static_assert(Complex_meta.members[1].value == 3);
static_assert(Complex_meta.members[2].value == 4);
static_assert(Complex_meta.members[3].value == 5);

static_assert(Complex_meta.members[0].index == 0);
static_assert(Complex_meta.members[1].index == 1);
static_assert(Complex_meta.members[2].index == 2);
static_assert(Complex_meta.members[3].index == 3);


int main()
{
    //enum meta objects are accessible with the _meta object
    //meta object has 'string' for full enum declaration string and 'members' for an array of all members
    //each member is an object of type MetaEnumMember
    std::cout << "global string: " << Global_meta.string << "\n";
    std::cout << "global count: " << Global_meta.members.size() << "\n";
    std::cout << "global class string: " << GlobalClass_meta.string << "\n";
    std::cout << "global class count: " << GlobalClass_meta.members.size() << "\n";
    std::cout << "nested string: " << Nester::Nested_meta.string << "\n";
    std::cout << "nested count: " << Nester::Nested_meta.members.size() << "\n";
    std::cout << "nested class string: " << Nester::NestedClass_meta.string << "\n";
    std::cout << "nested class count: " << Nester::NestedClass_meta.members.size() << "\n\n";

    //enum member objects have the following members:
    std::cout << "global members:\n";
    for(const auto& enumMember : Global_meta.members)
    {
        using UnderlyingType = decltype(Global_meta)::UnderlyingType;
        std::cout << "index=" << enumMember.index << ", name='" << enumMember.name << "', value: " << static_cast<UnderlyingType>(enumMember.value) << ", string='" << enumMember.string << "'\n"; 
    }
    std::cout << "\n";

    //helper functions are defined for convenience that operate on the _meta datastructure
    //value_to_string gets the name of an enum value and '__INVALID_ENUM_VAL__' on failure
    std::cout << "value_to_string: input=" << Nester::NestedB << " output='" << Nester::Nested_value_to_string(Nester::NestedB) << "'\n";

    //these are different ways to access the meta enum member objects. they return an std::optional which will be empty on bad input
    std::cout << "meta_from_name accesses through name. input=" << "NestedClassA" << " found_index=" << Nester::NestedClass_meta_from_name("NestedClassA")->index << "\n";
    std::cout << "meta_from_value accesses through enum value. input=" << Nester::NestedB << " found_index=" << Nester::Nested_meta_from_value(Nester::NestedB)->index << "\n";
    std::cout << "meta_from_index accesses through index. input=" << 2 << " found_name='" << GlobalClass_meta_from_index(2)->name << "'\n";
}