Comment by MyOutfitIsVague

The MRuby embedding API isn't a whole lot like Lua's. Lua is a fantastic experience to embed. You might have to futz with the registry to store Lua objects in a C struct, but the abstraction allows you to almost never have to actually worry about the VM internals or the GC directly. Mruby is a lot more like MRI Ruby's API. Raw objects are exposed to you, you have to turn off strict aliasing because inheritance is implemented by the old "common meta struct as first member" idiom, you have to manually trigger VM collecting in long-running C code ( https://github.com/mruby/mruby/blob/master/doc/guides/gc-are... ), getting args in a C function involves a variadic scanf-style function. The most striking difference is documentation. The documentation of the mruby C API is actually "read the headers". There are many seemingly redundant functions that look like they do the same thing, completely without explanatory comments, or minimal inscrutable comments:

    /* mrb_gc_protect() leaves the object in the arena */
    MRB_API void mrb_gc_protect(mrb_state *mrb, mrb_value obj);
    /* mrb_gc_register() keeps the object from GC. */
    MRB_API void mrb_gc_register(mrb_state *mrb, mrb_value obj);
    /* mrb_gc_unregister() removes the object from GC root. */
    MRB_API void mrb_gc_unregister(mrb_state *mrb, mrb_value obj);

I'd rather work with Ruby as a language than Lua, but I'd much rather work with Lua than Mruby for the documentation and API alone. If mruby had anything close to the Lua reference documentation, I'd be all over it. As-is, embedding mruby kind of sucks, which is a real shame.