Re: Combining modules and namespaces

Hi Hans

A couple of ideas:
1. Try using the 'cstype' typemap to add in the appropriate namespace to
the C# type, thus qualifying with a C# namespace.
2. SWIG mirrors the C++ API, so how about changing your C++ API to use the
multiple namespaces and use -nspace with SWIG. For C++ users, you can
always add in a 'using' statement to put them all back into the  one C++
namespace. So effectively no change for C++ users.

William

On Tue, 28 Jan 2020 at 13:46, Hans Packet <[email protected]> wrote:

> I'm trying generate C# bindings for a c++ API, and I'm running into
> problems with the combination of modules and namespaces.
>
> Some context on the problem I'm trying to solve: most of my c++ API is
> defined in a single namespace. For the C# API, it was preferred to have a
> more finegrained namespace structure. As far as I can see, the nspace
> feature can't accomplish that exactly though. For that reason, I have tried
> to use an alternative approach: split up the swig binding into multiple
> modules (one per namespace), and use the -namespace cl argument for each of
> the modules. Note that many of the modules depend on other modules. This
> works well, except that I run into a few problems:
>
> a) Other modules don't know anything about the namespace of an other
> module. I'm working around this by adding
>   - %typemap(csimports)
>   - %pragma(csharp) imclassimports
> This works ok, but it is manual work, i.e. harder to maintain. This is not
> a critical problem, but it makes the definition files harder to write.
>
> b) I end up with naming clashes in a very specific case. When a method
> argment type has the same name as the method itself, C# doesn't correctly
> resolve this. Example of the generated C# code:
>
> using Ns;
>
> void Rectangle(Rectangle rect) {
>   xxxPINVOKE.Xxx_Rectangle(swigCPtr, Rectangle.getCPtr(rect));
>   // ...
> }
>
> When using the nspace feature (which I probably can't use), this is not an
> issue, because the generated C# code ends up as:
>
> void Rectangle(Ns.Rectangle rect) {
>   xxxPINVOKE.Xxx_Rectangle(swigCPtr, Ns.Rectangle.getCPtr(rect));
>   // ...
> }
>
> You could argue that a method name should not be the same as the method
> argument's type, but in many cases (within the naming conventions that are
> used), it does make sense. So I would like to avoid renaming the methods if
> possible.
>
>
> My general question would be: Am I taking the correct approach to solve
> the 'single c++ namespace -> multiple C# namespaces' problem ? Or is there
> a better way to do this ? If you have suggestions to solve the sub-problems
> (a) and (b), that would be welcome too.
>
> Note: I came across a similar question in this mailing list, but it
> doesn't give a complete solution to my problem. It's also 10 years old, so
> a better solution might be available now.
> https://sourceforge.net/p/swig/mailman/message/24058732/
>
> Let me know if you need more information.
>
> Thanks,
> Hans
> _______________________________________________
> Swig-user mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/swig-user
>

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