Sly

Jul 20, 2023

Sylvester the Cat’s Common Lisp IDE for Emacs

SLY is a fork of SLIME. We track its bugfixes, particularly to the implementation backends. All SLIME’s familiar features debugger, inspector, xref, etc… are still available, with improved overall UX.

SLY’s highlights are

  • 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 them.
  • 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 stage.


Checkout these related ports:
  • Zile - Small emacs-like text editor
  • Yudit - Multi-lingual Unicode text editor with TTF support
  • Xvile - VI Like Emacs -- X11 version
  • Xmlcopyeditor - Fast validating XML editor
  • Xi-term - Terminal frontend for xi-editor
  • Xi-core - Modern editor backend written in Rust
  • Xed - Small but powerful text editor for GTK
  • Xcoral - Multiwindow mouse-based text editor for X
  • Wxhexeditor - Graphical hex editor for big files with x86 disassembly support
  • Wordgrinder - Simple Unicode-aware console and X11-based word processor
  • With-editor - Use the Emacsclient as the $$EDITOR of child processes
  • With-editor-devel - Use the Emacsclient as the $$EDITOR of child processes
  • Web-mode - Autonomous Emacs major-mode for editing web templates
  • Vscode - Visual Studio Code - Open Source ("Code - OSS")
  • Vis - Vi-like editor based on Plan 9's structural regular expressions