The docs mention how to define a js function and use it as a C function pointer. How would one go the other way around?

I imagine this to be trivial as the lib already does this when searching for library symbols (which are just function pointers), and giving them the appropriate calling meta information. Yet I haven't found anything easily usable in the code.

I was trying to recreate the example_optimize_png in rust from the lodepng lib, but when setting my windowsize to 32768 on the encoders zlibsettings it panics with an index out of bounds error.

rustc 1.34.0 (91856ed52 2019-04-10)
macos 10.14.4

thread 'main' panicked at 'index out of bounds: t

On my way debugging and separating the issues listed in #60 I came across another thing that isn't related to async or threading.

An xpath context is non-functional after the document from which it was created goes out of scope and is dropped.
There is no warning or error. It just doesn't return any results any more.

Most fields denoting sizes (e.g. of keys) are marked as usize at the moment. To make it less ambiguous, the ones representing sizes in bits should be set to u16, u32 or other types unrelated to word size on current platform (as the size itself is not related to the memory of the platform)