@ghadi: “The MethodHandles have to get hot” is that per call site, i.e. per specific template instance?

I’m not sure of the implications of MethodHandle.partial

If I have two instances of {:foo <something> :bar <something>} at different locations in my code, is the MethodHandle reused? What about if the <somethings> are equal?

The templating methodhandle with its arguments is not reused, but the underlying raw handle is shared. MethodHandle.partial is actually MethodHandle.insertArguments (had to use the pseudocode to make it accessible)

And guess what, the performance doesn't pay off until about 4 map entries