Support complex data structures about nbind HOT 3 CLOSED

How about adding support for (some) STL containers like std::pair?
If nbind could define some typical types like std::pair<int,int> as well as provide their JS counterparts and default bindings, this would make passing such containers much easier.
(I am not sure if embind provides similar facilities...)

from nbind.

Embind supports both std::vector and emscripten::val for passing JavaScript arrays, and std::vector support is also planned for nbind very soon. Then std::map corresponding to JavaScript objects would be next.

More complicated structures have 2 issues. A JavaScript Array or Object might consist of different types of elements, so it's not mappable to a standard library type (unless the values are then like emscripten::val). Also, we don't know how it will be used in C++. If all the fields are needed, possibly several times, it would be better to copy the structure to the C++ heap to avoid constant round-trips across languages. But if just a few fields are needed, it's best not to copy everything and instead access them through function calls like Embind does.

In Node.js, C++ and JavaScript share the same heap and a good C++ API is available for accessing everything, so copying data to any other structure doesn't really make sense (except to std::vector for quick access in all sorts of algorithms). In Emscripten C++ has no access to the JavaScript heap in general and accessing the C++ heap from JavaScript is painful. Complicated structures should be processed fully in JavaScript to avoid bloat.

Finally, for targeting React Native or Cordova or similar, complicated data probably needs to pass through an Objective C, Swift or Java bridge and it would be easiest to serialize it somehow. Probably still not to JSON, but a binary format copied from one heap to another.

The syntax for accessing the data from C++ should be identical and sensible in all cases. This will take some long-term effort to figure out.

from nbind.

Let's track this in a project instead.

from nbind.