some thoughts on panama/jextract

[Maurizio Cimadamore]

On 08/01/2020 10:01, Samuel Audet wrote:
> The Java API that gets created for all these platforms is exactly the 
> same, and it works exactly the same on all these platforms as well. 
> That's the kind of thing the Java community needs, in my opinion. 

I agree that, as a user, the best case is to just download some Maven 
artifact that gives me the library I want (if it exists!!!!!) - no 
matter which platform I'm on, and have a single javadoc to go through to 
learn the API.

As we discussed on this thread, depending on the choices made by the 
API, this can sometimes be easy or hard to achieve. If a library creates 
portable type definitions, so that the layouts remain the same across 
platforms - or stays away from ambiguous types such as 'long' (which on 
Windows mean something else), then having a single API is indeed possible.

If the API is really ill-behaved, there are choices to be made. One 
platform could have more functions than another platform - what do you 
do? Or, some struct layouts might be completely incompatible (e.g. a 
struct in a platform has 3 fields and in another has 4). If you have 
these issues, no matter what tool you use to generate the Java bindings 
- you _have_ to make choices about what to do, and how to paper over the 
differences.

It is not Panama's job to tell you how to do that (paper over the 
differences) - I can imagine frameworks much more sophisticated (and 
higher level) applying various heuristics in order to try and compress 
all the extracted bindings into a uniform API.

Maurizio