https://github.com/kris-jusiak/vc
Virtual Concepts
https://github.com/kris-jusiak/vc
concepts dependency-injection dynamic-polymorphism mocking static-polymorphism type-erasure
Last synced: 11 months ago
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Virtual Concepts
- Host: GitHub
- URL: https://github.com/kris-jusiak/vc
- Owner: kris-jusiak
- Created: 2017-03-11T23:19:05.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2017-03-28T22:24:42.000Z (almost 9 years ago)
- Last Synced: 2025-03-27T22:43:09.221Z (11 months ago)
- Topics: concepts, dependency-injection, dynamic-polymorphism, mocking, static-polymorphism, type-erasure
- Language: C++
- Homepage:
- Size: 72.3 KB
- Stars: 8
- Watchers: 3
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
---------------------------------------
# Virtual Concepts
### Concept
```cpp
template
const auto Equality_comparable =
$requires(T)(auto a, auto b) (
bool(a == b),
bool(a != b)
);
```
```cpp
template
const auto Iterator() {
return CopyConstructible &&
CopyAssignable &&
Destructible &&
$requires(T)(auto&& t) (
*t,
typename decltype(t)::type
);
}
}
```
```cpp
template
const auto Callable(F f) {
return $requires(T)(auto&& t, Ts... args) (
R((t.*f)(args...));
)
}
```
```cpp
template
const auto Creatable = Callable($(create));
```
```cpp
struct Readable {
template
auto operator()() {
return CopyConstructible() &&
$requires(T)(auto&& t, std::ostream& os) (
os = (os << t)
) &&
Callable($(read));
}
};
```
### Implementation
```cpp
struct FileReader {
void read(int) const {
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
};
std::ostream& operator<<(std::ostream& os, FileReader&) {
return os;
}
```
### Usage
```cpp
int main() {
// constraint checking
static_assert(Equality_comparable, "");
static_assert(Readable{}.operator()(), "");
// template mocking
testing::GMock mockReadable;
EXPECT_CALL(mockReadable, read, 42);
mockReadable.read(42);
// type erasure - dynamic dispatch
type_erasure::any readable = FileReader{};
readable.read(42);
// type erasure mocking
readable = GMock{};
EXPECT_CALL(mock, read, 42);
readable.read(42);
}
```
### Dependency Injection - [[Boost].DI](https://github.com/boost-experimental/di)
```cpp
template // = 'Concept'
class App {
TReader reader; // static dispatch
type_erasure::any printer; // dynamic dispatch
public:
App(TReader reader, type_erasure::any printer)
: reader(reader), printer(printer)
{ }
void run() {
printer.print(reader.read());
}
};
int main() {
const auto injector = di::make_injector(
di::bind.to()
di::bind.to()
);
injector.create().run();
}
```
### Testing
```cpp
"should print read text"_test = [] {
constexpr auto value = 42;
auto [sut, mocks] = testing::make(); // creates System Under Test
// and Mocks
InSequence sequence;
EXPECT_CALL(mocks(), read).WillOnce(Return(value));
EXPECT_CALL(mocks(), print, value);
sut.run();
};
```
---
## Dependencies
* Concepts
* [STL](http://en.cppreference.com/w)
* Type Erasure (any)
* [dyno](https://github.com/ldionne/dyno)
* [Boost.Hana](https://github.com/boostorg/hana)
* [CallableTraits](https://github.com/badair/callable_traits)
* Mocking (GMock)
* [GUnit](https://github.com/cpp-testing/GUnit)
* [Google Test/Mock](https://github.com/google/googletest)
* Dependency Injection
* [[Boost].DI](https://github.com/boost-experimental/di)
## References
* [Concept Checking in C++11](http://ericniebler.com/2013/11/23/concept-checking-in-c11) | [Type requirements in C++](http://pfultz2.com/blog/2014/08/17/type-requirements)
* [A bit of background for concepts](https://isocpp.org/blog/2016/02/a-bit-of-background-for-concepts-and-cpp17-bjarne-stroustrup)
* [Concepts Lite](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3580.pdf)
* [Vitual Concepts Proposal](https://github.com/andyprowl/virtual-concepts/blob/master/draft/Dynamic%20Generic%20Programming%20with%20Virtual%20Concepts.pdf)
* [Concepts driven design with DI](http://boost-experimental.github.io/di/concepts-driven-design-with-di)
* [Static reflection](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0194r0.pdf)