Mirrow - A Template Meta Programming utility framework

mirrow is a TMP(template meta programming) utility framework in C++17. It aimed to make some utility to help programmer do TMP easier. Referenced meta and ponder.

Nowadays, mirrow has these parts:

• util: some common utilities
• srefl: static reflection framework
• drefl: dynamic reflection framework
• serd: a serialize framework based on reflection(serial with drefl&srefl) with TOML

📖 docs

util

util(utility) has some convenient utility to do TMP:

• type_list: compile-time type list. 🔬 unittest
• function_traits: compile-time function info trait. 🔬 unittest
• variable_traits: compile-time variable info trait. 🔬 unittest
• const_str: compile-time string. 🔬 unittest

srefl

static reflection framework. 🔬 do reflect unittest, get reflected info unittest

To reflect your class, you must do like this:

// your class
class Foo final {
public:
    void foo() {}
    void foo(int) {}
    void foo(float) {}
    void another() {}

    int value_1 = 1;
    int value_2 = 2;
};

// include srefl_begin.hpp
#include "mirrow/srefl/srefl_begin.hpp"
// do your reflection
srefl_class(Foo,
    ctors()
    fields(
        field(static_cast<void(Foo::*)(void)>(&Foo::foo)),
        field(static_cast<void(Foo::*)(int)>(&Foo::foo)),
        field(static_cast<void(Foo::*)(float)>(&Foo::foo)),
        field(&Foo::another),
        field(&Foo::value_1),
        field(&Foo::value_2)
    )
)
// include srefl_end.hpp
#include "mirrow/srefl/srefl_end.hpp"

srefl_begin.hpp provide a bunch of macros to help you regist your class. And srefl_end.hpp will #undef these macros to avoid pollute your codes.

Then, use srefl_class(<your class>, ...) to start regist your class. use ctors() to regist constructors(optional), use fields(...) to start regist member/static variable/functions.

After reflect, you can use auto refl = reflect<Foo>(); to get reflected informations. And visit member variables:

refl.visit_member_variables([&vars](auto&& value) {
    vars.push_back(value.name());
});

visit function/static fields is WIP, it is easy to implement but currently I don't need them

drefl

dynamic reflection framework.

any

any is similar to std::any, but support ownership 🔬unittest

any has 3 ownership(defined in any::access_type):

• Null: don't contain data
• ConstRef: const reference to a value
• Ref: mutable reference to a value
• Copy: the data's ownership is any itself, when any destruct, data will destruct together

use any_make_xxx to create an any from ownership:

int a = 123;
auto cref = mirrow::drefl::any_make_constref(a);	// make a const reference
auto ref = mirrow::drefl::any_make_ref(a);	// make a reference
auto new_value = mirrow::drefl::any_make_copy(a); // copy a to any inner data

and use member function constref(), ref(), copy(), steal() to translate ownership.

use try_cast() & try_cast_const() to cast any to a determined type. use try_cast() on ConstRef any will throw a bad_any_access exception and return nullptr.

factory

factory is where you reflect your type:microscope:unittest

register your class by:

struct Person {
    std::string name;
    float height;
    const bool hasChild;
    const Person* couple;
};

// in main():
mirrow::drefl::factory<Person>::instance()
              .regist("Person")
              .property("name", &Person::name)
              .property("height", &Person::height)
              .property("hasChild", &Person::hasChild)
              .property("couple", &Person::couple);

or register your enum by:

enum class MyEnum {
        Value1 = 1,
        Value2 = 2,
        Value3 = 3,
    };

// in main():
auto& inst = mirrow::drefl::factory<MyEnum>::instance()
    .regist("MyEnum")
    .add("Value1", MyEnum::Value1)
    .add("Value2", MyEnum::Value2)
    .add("Value3", MyEnum::Value3);	

then use

auto info = mirrow::drefl::typeinfo<Person>();

to get registered type information;

NOTE: currently we don't support register member function.

there are may type information you can access(by member functionas_xxx()):

• enum_info: enumerates
• numeric: numerics(int,float,char...)
• boolean: boolean
• string:std::string or std::string_view (may add const char* support later)
• pointer: pointers like T*, T* const, T**...
• array: std::vector, std::array, std::list, T[N]
• class: other classes

future support:

• map: std::unordered_map, std::map
• set: std::unordered_set, std::set
• optional: std::optional
• smart points: std::unique_ptr. std::shared_ptr
• pair: std::pair

serd

A serialize/deserialize tools based on dynamic/static reflection.

serd provide two serialize/deserialize method: dynamic and static, which need you use dynamic/static reflection to provide type info first.

dynamic reflection based serialize 🔬 unittest static reflection based serialize 🔬 unittest

After reflected type, you can do serialize like:

type instance;  // create an instance

// use static reflection based serialize
toml::table tbl;
mirrow::serd::srefl::serialize(instance, tbl);
// use static reflection based deserialize
mirrow::serd::srefl::deserialize(tbl, instance);

// convert instance to any to prepare serialize
mirrow::drefl::reference_any data{instance};
// use dynamic reflection based serialize
toml::table tbl = mirrow::serd::drefl::serialize(data);
// use dynamic reflection based deserialize
mirrow::serd::drefl::deserialize(tbl, data);

If you don't know which toml node would be serialize/deserialize, you can use mirrow::serd::srefl::serialize_destination_type_t<your-type> to get the type.

custom serialize function

all serialize and deserialize function will iterate all member fields in your type info and [de]serialize them. If field not exists when deserialize, it will log and ignore this field.

There are some inner-support type:

• numeric(integer like int, char ..., and floating point(float, double))
• bool
• std::vector
• std::array
• std::optional
• std::unordered_map
• std::unordered_set

If you want do specific [de]serialize method on your own type, here:

for static [de]serialize, need two step:

namespace mirrow::serd::srefl {

// 1. tell serd which toml node you want to serialize to
// use SFINEA
namespace impl {

template <>
struct serialize_destination_type<your_own_type> {
    // we want [de]serialize to/from toml::value
    using type = toml::value<your_own_type>;
};

}


// 2. provide your [de]serialize method
// also use SFINEA, serialize function
template <typename T>
std::enable_if_t<std::is_same_v<your_own_type, T>>
serialize(const T& value, serialize_destination_type_t<T>& node) {
    // try put value into node
    ...
}

// also use SFINEA, deserialize function
template <typename T>
std::enable_if_t<std::is_same_v<T, your_own_type>>
deserialize(const toml::node& node, T& elem) {
    // try parse elem from node
    ...
}

}

for dynamic [de]serialize, you need regist your function into serialize_method_storage at runtime:

mirrow::serd::drefl::serialize_method_storage::instance().regist(type_info, serialize_fn, deserialize_fn);

the second and thrid param is your serialize/deserialize function, must be:

// serialize
void serialize(toml::node&, const any&)>;
// deserialize
void deserialize(const toml::node&, any&)>;

after these, you can use serialize/deserialize:

Person p;
mirrow::drefl::any any = mirrow::drefl::any_make_ref(p);

// serialize to toml node
auto tbl = ::mirrow::serd::drefl::serialize(any);

// deserialize from toml node
::mirrow::serd::drefl::deserialize(p, tbl);