C++ SWIG annoyances for Go

[Yutong Zhao]

I'm not sure who else here has been wrapping C++ code for Go, but some of the annoyances I've ran into are:

-lack of shared_ptr typemaps for Go (both std:: and boost::)

-std::vector doesn't map to go slices

-std::map doesn't map to go map

-go doesn't support permit overloaded functions

-not clear to me how to wrap virtual functions

If anyone has any suggestions for the problems above I'd love to hear solutions. Alternatively, I was wondering what were some of other issues people here have ran into?

[Ian Lance Taylor]

On Sun, Sep 13, 2015 at 12:10 PM, Yutong Zhao <prot...@gmail.com> wrote:
>
> I'm not sure who else here has been wrapping C++ code for Go, but some of
> the annoyances I've ran into are:
>
> -lack of shared_ptr typemaps for Go (both std:: and boost::)

This is hard to solve. We could use finalizers on the Go side but
it's hard to ensure that they only run when the pointer is no longer
being used.

> -std::vector doesn't map to go slices
> -std::map doesn't map to go map

What would these mean? Go slices and maps are reference types. C++
vector and map are not.

> -go doesn't support permit overloaded functions

Well, yes. It does permit SWIG wrapping C++ overloaded functions,
though.

> -not clear to me how to wrap virtual functions

This could mean a few different things, and I'm not sure what you
mean. Have you seen the code in misc/swig/callback in the Go
repository?


In general, Go and C++ are different languages. It's unrealistic to
safely and efficiently convert all constructs between them. I view
SWIG as doing the mechanical parts of calling between the languages.
You still have to write Go to provide an idiomatic Go interface.

Ian