replace c++ with go + swig

Question

I recently asked this question https://softwareengineering.stackexchange.com/questions/129076/go-instead-of-c-c-with-cgo and got some very interesting input. However there's a mistake in my question: I assumed cgo could also be used to access c++ code but that's not possible. Instead you need to use SWIG.

The go faq says "The cgo program provides the mechanism for a “foreign function interface” to allow safe calling of C libraries from Go code. SWIG extends this capability to C++ libraries. "

my question: Is it possible to access high-level c++ frameworks such as QT with SWIG + Go and get productive? I'd like to use Go as a "scripting language" to utilize c++ libraries.

Have you any experience with go and swig? Are there pitfalls I have to be aware of?

Update/Answer: I've asked this over IRC too and I think the question is solved:

SWIG is a rather clean way of interfacing c++ code from other languages. Sadly matching the types of c++ to something like go can be very complex and in most cases you have to specify the mapping yourself. That means that SWIG is a good way to leverage an existing codebase to reuse already written algorithms. However mapping a library like Qt to go will take you ages. Mind it's surely possible but you don't want to do it.

Those of you that came here for gui programming with go might want try go-gtk or the go version of wxWidgets.

Answer 1

Is it possible? Yes.

Can it be done in a reasonably short period of time? No.

If you go back and look at other projects that have taken large frameworks and tried to put an abstraction layer on it, you'll find most are "incomplete". You can probably make a fairly good start and get some initial wrappers in place, but generally even the work to get the simple cases solved takes time when there is a lot of underlying code to wrap, even with automated tools (which help, but are never a complete solution). And then... you get to the nasty remaining 10% that will take you forever (ok, a really really long time at least). And then think about how it's a changing target in the first place. Qt, for example, is about to release the next major rewrite.

Generally, it's safest to stick to the framework language that the framework was designed for. Though many have language extensions within the project itself. For example, for Qt you should check out QML, which provides (among many other things) a javascript binding to Qt. Sort of. But it might meet your "scripting" requirement.

Answer 2

A relevant update on this issue: it is now possible to interact with C++ using cgo with this CL, which is merged for Go 1.2. It is limited, however, to C-like functions calls, and classes, methods and C++ goodies are not supported (yet, I hope).