I am much happier with my second attempt at an OCaml binding for Oracle Coherence. This way is easier to build, easier to use, and I could reuse all of the C++ code from my first attempt. See the code on GitHub.

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1. Use a class (or classes) written in pure C++ to interact with Coherence
2. Use extern "C" functions first to instantiate an object from (1) and return an object pointer to OCaml, then to invoke methods via that pointer.
3. From OCaml, call the function to create the object, then pass the pointer from (2) into the other C functions using the normal OCaml/C interface
4. Pre- and post- grid operations implemented in OCaml

The next challenge will be to use MapListener/Continuous Query to execute code in OCaml in response to events within the grid – if possible, configuring it from the OCaml side. And then to do it with more complex data structures than simple strings.