Lisp

Lisp is a historical functional and metaprogramming language first appearing in 1958.

Hello World

; BEGIN_FRAGLET
(format t "Hello World!")
; END_FRAGLET

Coding Guide

Language Version

SBCL (Steel Bank Common Lisp)

Execution Model

• Expressions execute in order, exactly as written
• Top-level execution is single pass
• Session ends when execution completes
• Use format with t as the destination for output to stdout

Key Characteristics

• S-expression syntax
• Case-sensitive (though reader normalizes symbols by default)
• Dynamic typing
• Functions are first-class values

Fragment Authoring

Write valid Common Lisp expressions. Your fragment becomes the script body. They execute in order, exactly as written. Define functions before using them.

Available Packages

Standard Common Lisp functions are available. No additional ASDF systems are pre-installed.

Common Patterns

• Output: (format t "message~%")
• Function definition: (defun function-name (args) body)
• Let binding: (let ((var value)) body)
• List processing: (mapcar #'function list)
• Reduce: (reduce #'+ list)
• Conditionals: (if condition then else)

Examples

;; Simple output
(format t "Hello, World!~%")

;; Function definition
(defun greet (name)
  (format t "Hello, ~a!~%" name))

(greet "Alice")

;; List processing
(let ((numbers '(1 2 3 4 5)))
  (let ((squared (mapcar (lambda (x) (* x x)) numbers)))
    (format t "Sum of squares: ~a~%" (reduce #'+ squared))))

Caveats

• Fragments should be idempotent—design them so repeated runs succeed without manual cleanup
• For deterministic behavior, avoid randomness or set seeds before generating random values
• Each run starts fresh—include all setup logic in the fragment itself
• Call (quit) if you need to exit explicitly, though execution ends automatically when complete

Fraglet Scripts

Echo Args

#!/usr/bin/env -S fragletc --vein=lisp
(format t "Args: ~{~a~^ ~}~%" (cdr sb-ext:*posix-argv*))

List Process

#!/usr/bin/env -S fragletc --vein=lisp
(let ((numbers '(1 2 3 4 5)))
  (let ((squared (mapcar (lambda (x) (* x x)) numbers)))
    (format t "Sum of squares: ~a~%" (reduce #'+ squared))))

Stdin Upper

#!/usr/bin/env -S fragletc --vein=lisp
(loop for line = (read-line *standard-input* nil)
      while line
      do (format t "~A~%" (string-upcase line)))

Test

#!/usr/bin/env -S fragletc --vein=lisp
(format t "Hello World!")

Connections

Container Info