[foreign-abi] On invokers

[Maurizio Cimadamore]

On 24/09/2019 23:31, John Rose wrote:
> Maurizio, my reaction to your observations about how we might have 
> missed the “full glass” of
> full generality is simply that, if a meta-ABI design is known to be 
> flexible across known degrees of
> freedom,. then it is likely that it can be adapted to new, unforeseen 
> degrees of freedom, as they
> become important.

To be clear, in case what I said came off the wrong way - it was not my 
intention to criticize this work in any way. It was more of a call for 
being honest about what this effort is about; programmable, or pluggable 
invoker might evoke the idea that users can mix and match ABIs according 
to their tastes - e.g. some sort of API that lets you control all the 
knobs - present and future. I think the best we can do at this point in 
time is, as you say, generalize over the case we know about - and hope 
(with good reason) that the new cases we'll see will be adapted with 
ease. In other words, our goal here is to devise an invoker that is 
general enough to supersede the invokers we currently have (of which we 
have three: universal, link2native and JNI-based direct invoker), and I 
was trying to resist to the sirens singing for a general meta-ABI API. 
That might come, in time, or maybe never will - for now the goal is to 
make the implementation saner, so that we can more rapidly adapt across 
platforms.

Maurizio