Interactive Common Lisp

A modern REPL experience with syntax highlighting, auto-completion, data visualization, and AI integration

Works with SBCL, CCL, ECL, ABCL, Clasp, and Roswell

$ icl
;; ICL - Interactive Common Lisp
CL-USER> (defun greet (name)
           (format nil "Hello, ~A!" name))
=> GREET
CL-USER> (greet "Lisper")
=> "Hello, Lisper!"
CL-USER> ▌

Three Ways to REPL

Use ICL however you prefer

⌨

Terminal

Syntax highlighting, paredit, tab completion, and interactive object inspector

icl

🌐

Browser

Package browser, symbol inspector, class hierarchies, and data visualization

icl -b

📝

Emacs

Integrates with SLY/SLIME for synchronized browser visualizations

M-x icl

Flame Graph Profiling

Profile any expression and explore the results in an interactive Speedscope visualization. Identify performance bottlenecks with Time Order, Left Heavy, and Sandwich views.

,flame (my-expensive-function)

Features

🎨

Syntax Highlighting

Colorized input with matching parentheses

🔧

Paredit Mode

Structural editing with balanced parens

📊

Data Visualization

Hash tables, classes, Vega-Lite, Mermaid

🔥

Flame Graphs

Interactive Speedscope profiling

🤖

AI Integration

Explain code with Claude, Gemini, Codex

🔍

Object Inspector

TUI for exploring complex objects

📦

Multiple Lisps

SBCL, CCL, ECL, ABCL, Clasp, Roswell

🔬

Disassembly View

Visualize function machine code

Installation

Pre-built Binaries

Download RPM, DEB, or Windows installers

Download →

Roswell

ros install atgreen/icl

Build from Source

git clone https://github.com/atgreen/icl.git
cd icl && ocicl install && make