[JonChesterfield]

> Things have changed. Fexprs are coming back in a big way.

I agree that Lisp dropped the ball on fexpr. It seems to be a combination of dynamic scoping, well founded performance concerns and some conflation of syntax and semantics. The special forms must appear under their own names thing is a related performance hack.

Lisp no longer has performance concerns. SBCL is excellent. Speculative JIT techniques would roll right over the "is this a function or a fexpr?" branch in apply with no trouble. I'm convinced there's no inherent overhead there.

I don't see much evidence that fexpr's are coming back though. Kernel is superb, though I'm unconvinced by the handling of cycles, but doesn't seem to be in use. Qi/shen is a similar sort of do-things-right effort with limited uptake. What do you have in mind?

My working theory is that lisp is niche enough that and a better lisp (which I contend kernel is - replacing the layers of macros with fexpr guts a lot of complexity from the language, and that was meant to be the driving motive behind Scheme) hits a subset of the first niche.

[pwpwp]

Those things take time. I am convinced that the next big Lisp dialect will be a Kernel.