# KidLisp Language Reference *Documentation for the KidLisp programming language in Aesthetic Computer* ## Overview KidLisp is a Lisp-based visual programming language designed for creating interactive art and animations in Aesthetic Computer. It provides a simple, expressive syntax for graphics, animation, and user interaction. ## Basic Syntax ### S-Expressions KidLisp uses S-expressions (parenthesized lists) where the first element is a function name followed by arguments: ```lisp (function-name arg1 arg2 arg3) ``` ### Comments ```lisp ; This is a comment ; Comments start with semicolon and go to end of line ``` ### Multi-line Expressions Expressions can span multiple lines for readability: ```lisp (box 10 20 100 150 "outline") ``` ## Core Language Features ### Variables Define variables with `def`: ```lisp (def x 10) (def color "red") (def size 50) ``` **Important**: Variable names cannot contain dashes/hyphens (-) as they are parsed as subtraction: - ✅ Valid: `myVar`, `line_width`, `color2` - ❌ Invalid: `my-var`, `line-width` (parsed as subtraction) ### Functions Define reusable functions with `later`: ```lisp (later square x y size (box x y size size)) ; Call the function (square 50 50 100) ``` ### Math Operations ```lisp (+ 5 3 2) ; Addition: 10 (- 10 3) ; Subtraction: 7 (* 4 5 2) ; Multiplication: 40 (/ 20 4) ; Division: 5 ``` ## Graphics Functions ### Screen Management ```lisp (wipe "black") ; Clear screen with color (wipe 255 0 0) ; Clear with RGB red (resolution 800 600) ; Set canvas size ``` ### Drawing Colors ```lisp (ink "red") ; Set color by name (ink 255 0 0) ; Set RGB color (ink "blue" 128) ; Set color with transparency (ink 100 200 255 180) ; RGBA color ``` ### Drawing Primitives ```lisp (line 10 10 90 90) ; Draw line (box 50 50 100 75) ; Draw rectangle (circle 100 100 50) ; Draw circle (tri 50 10 10 90 90 90) …