SLY is Sylvester the Cat's Common Lisp IDE for Emacs.
SLY is a fork of SLIME. All SLIME's familar features (debugger, inspector,
xref, etc...) are still available, with improved overall UX. SLY's
A full-featured REPL based on Emacs's comint.el. Everything can be copied
to the REPL;
Stickers, or live code annotations that record values as code traverses
Flex-style completion out-of-the-box, using Emacs's completion API.
Company, Helm, and other supported natively, no plugin required;
An interactive Trace Dialog;
Cleanly ASDF-loaded by default, including contribs, enabled out-of-the-box;
Multiple inspectors and multiple REPLs;
"Presentations" replaced by interactive backreferences which highlight the
object and remain stable throughout the REPL session;
Support for NAMED-READTABLES, macrostep.el and quicklisp.
A portable, annotation-based stepper in early but functional prototype