I don’t think your problem has anything to do with Ada itself. You’d have the same issues using Rust or Go or Swift or Zig or whatever - if you make heavy use of C++’s features, it can make interop with other languages harder
100% It seems like any language other than C has poor interoperability with anything other than C. C++ doesn't know how to deal with the rust borrow checker. Go will have issues with both.
D is an exception - D supports C++ (I'm not sure how or how well, but they at least have some C++ ABI constructors). there are others (some languages running on the JVM usually work with java not C)
> It seems like any language other than C has poor interoperability with anything other than C
Interop between C and classic 3rd generation languages such as Fortran, Pascal, Basic, COBOL, Algol, PL/I, tends to not be that hard [0] – because their feature set is at roughly the same level as C's: just functions/procedures without polymorphism or inheritance, relatively simple (non-OO) data types, etc.
Whereas, C++/Go/Rust/Swift/Ada/etc all add lots of complex features on top, and it is when you use all those complex features, interop with C and classic 3GLs gets harder. Sometimes you can define a subset which omits many of those more complex features and makes interop easier, but then you lose out on the benefits those features bring
[0] one complexity, is for historical reasons, sometimes these languages use different calling conventions than C – but on platforms on which that is an issue, it isn't uncommon for C compilers to support those additional calling conventions as an extension, and newer implementations of those languages for newer platforms are generally converging to C's calling conventions. Another is that some of these languages have data types for which C lacks native support – e.g. many COBOL implementations feature BCD arithmetic – but it is easy to write a routine in C to convert BCD to binary and back.
All the while I've been calling C and C++ code (hard stuff but C++ interop is ... hard) from Ada for 15+ years and calling Ada code from C too. python from Ada and Ada from python too. Ada from Java through JNI. Writing postgres extensions in Ada. It's not always a panacea but it's possible.
