> Writing performant code in Common Lisp is not for everyone, and it most certainly cannot be done portably; what might run fast on one implementation may run p

> Writing performant code in Common Lisp is not for everyone, and it most certainly cannot be done portably; what might run fast on one implementation may run poorly on another. The moment you start writing implementation-specific code, in my honest opinion, you are better off using another programming language (which can also be considered writing implementation-specific code). can you please elaborate on this conclusion - "better off using another language"? i find it interesting because i happen to fit into this category - ie writing performant code in cl (sbcl). besides sbcl no other implementation interests me (actually maybe CLASP) and i care very little if my code is portable; hence marked as cl (sbcl). sbcl allows me to do all sorts of optimizations that not even julia has. and cl with emacs+slime is to me by far the most enjoyable hacking experience the fact that you are writing a graphics engine (which is hardware dependent if performance is what you want) suggests to me that you too should not spend so much time on portability. i think implementation specific libraries in cl should be welcomed. like with people, if you try to get everyone to like you you are not going to get very far