Common Lisp Online Compiler
Write and run Common Lisp code online directly from your browser with our free Online Common Lisp Compiler. Test Lisp expressions, functions, macros, lists, and other Common Lisp features without installing SBCL, CLISP, Emacs, SLIME, or configuring a local development environment.
How to Use This Common Lisp Compiler
- Write or paste your Common Lisp code
Enter your program in the Code Editor. You can test expressions, define functions, work with lists, use conditionals, and experiment with supported Common Lisp features. - Click the Run button
Select Run to execute your Common Lisp program. If your code contains a syntax or runtime error, review the returned message and update the relevant expression. - Check the Output screen
Your program result appears in the Output panel. Use the available controls to copy, download, or delete the output before running another example.
Key Features
- Free Online Common Lisp Compiler: Write and execute Common Lisp code directly from a modern web browser.
- Zero Installation: No need to install SBCL, CLISP, Emacs, SLIME, or another local Lisp development setup for supported programs.
- Instant Execution: Click Run and quickly view program output or error feedback in the Output screen.
- Standard Common Lisp Syntax: Practice functions, variables, lists, conditionals, recursion, higher-order functions, and other core language concepts.
- Macros and Functional Programming: Experiment with Common Lisp’s macro system and functional programming techniques supported by the execution environment.
- Dark and Light Mode: Switch the Code Editor theme for a more comfortable coding experience.
- Output Controls: Copy, download, or clear generated output directly from the Output panel.
- Useful for Learning and Testing: Suitable for beginners learning Lisp syntax as well as experienced developers testing small expressions or algorithms.
1. How do I print output in this Common Lisp compiler?
Common Lisp provides several output functions. You can use format for formatted text:
You can also use print:
Enter the code in the Code Editor, click Run, and view the result in the Output screen.
2. Do I need to install SBCL or CLISP to use this compiler?
No. You can run supported Common Lisp code directly through this Online Common Lisp Compiler without installing SBCL, CLISP, or configuring a local Lisp environment.
For larger applications, external libraries, advanced debugging, or full project development, a local Common Lisp implementation may still be more appropriate.
3. Does this compiler support standard Common Lisp functions and macros?
The compiler is intended to support standard Common Lisp syntax and core language features available in its execution environment. This can include functions such as car, cdr, cons, mapcar, reduce, length, and macros such as defmacro, when, and unless.
Support for third-party libraries, implementation-specific extensions, or external packages may vary.
4. How do I define and call a function in Common Lisp?
Use defun to create a named function. For example:
Here, square accepts one argument and returns its value multiplied by itself. Click Run to execute the code and view the result in the Output panel.