SWIG + CSharp samples

CPP	-> Main library
CSharp -> C++ library proxy (wrapper)
		-> C# Library
		-> C# Tests

Loosely based on CSharpOdeLibrary and my NEC'2015 talk. Requires SWIG 3 installed in your path.

• You create C++ library
• You minimize its interface and build its dll+lib into Build folder
• You create a SWIG .i wrapper
• You ran SWIG code generator
• create a C++ wrapper dll based on generated files, connect it to your library, and build its dll into Build folder
• create a C# wrapper library based on generated files, and build its dll into Build folder
• create a C# tests project to test C# library and build it into Build folder

So you shall get:

• A pure C++ library with no exports (build for all platforms you need)
• A C++ wrapper library with exports for each language you support, (build for all platforms you need)
• A library in target language
• A test case library
• A bench mark library if required

• Pure C APIs with C++ backend make development iterations longer.
• It is important to keep architecture as simple and bare bone C++ as possible.
• Any standard library object can cause pain in one language or another (like for example std::complex).
• Minimize header file includes required for your API.
• Templates require special treatment and are not there in generated wrappers code.
• Create special target language helper objects that could help integration of your library into users codebase.
• Configure build order correctly

• use %module(directors="1") ModuleName; and %feature("director"); to get inheritance
• use template specialization alike %template(StateType) std::vector<double>; inside .i file in conjunction with type defenitions alike typedef std::vector<T> StateType; in your C++ interface
• use %shared_ptr(ClassName) for an object to be passable as shared_ptr, if done correctly Stuff like SWIGTYPE_p_std__shared_ptrT_%TYPE_NAME%_t should not appear - lock for the order
• In case of shared_ptr use, note that GC collectable objects that inherit from C++ code will be bound to GC rules! Thus if you have a shared_ptr in object B C++ code you must create an object BTargetLanguage that would keep a reference in target language to that shared_ptr (see BSharp implementation and TestWithNew for reference).
• Write shared_ptr(A) before %feature("director") A;

• Write events/delegates using virtual class functions (no C pointers, std::function's etc)
• Write Interfaces as pure virtual classes
• Use single inheritance trees
• Wrap all non std library objects needed externally

• Build Order:
  • Compile Library (C++)
  • Call SWIG (run on .i file)
  • Compile Wrapper Library (C++)
  • Compile Wrapper Library (C#),
  • Compile tests
• Install mixed enviroment C++ + target language