| #lang racket/base | |
| ;;; License: [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0) or | |
| ;;; [MIT license](http://opensource.org/licenses/MIT) at your option. | |
| (require quickscript | |
| quickscript/base | |
| racket/class | |
| racket/file | |
| racket/match |
| #lang racket/base | |
| #| | |
| Three color LED connected to RPi GPIO pins 2 3 4. | |
| The process is pretty straightforward. | |
| 1. Use FFI to get open and mmap /dev/gpiomem | |
| 2. Use FFI ptr-ref and ptr-set! to change the gpio registers |
| #lang racket | |
| ;; A CPS interpreter for a CBV language written in syntax-rules | |
| ;; e ::= 'd literal | |
| ;; | x variable | |
| ;; | (e e) application | |
| ;; | (λ (x) e) abstraction | |
| ;; (eval e) interprets e in an environment |
| #lang racket | |
| ;; License: [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0) or | |
| ;; [MIT license](http://opensource.org/licenses/MIT) at your option. | |
| (require racket/gui/base | |
| pict) | |
| (define line-width-init 1) |
| #lang racket/base | |
| (struct %class [parent ivars methods] #:transparent) | |
| (struct %object [class ivars] #:transparent) | |
| (define (new class vals) | |
| (%object class vals)) | |
| (define (send obj method-name args) | |
| (define method (lookup-method (object-class obj) method-name)) |
| #!/usr/bin/awk -f | |
| # This program is a copy of guff, a plot device. https://github.com/silentbicycle/guff | |
| # My copy here is written in awk instead of C, has no compelling benefit. | |
| # Public domain. @thingskatedid | |
| # Run as awk -v x=xyz ... or env variables for stuff? | |
| # Assumptions: the data is evenly spaced along the x-axis | |
| # TODO: moving average |
This gist contains examples of how to build different kinds of control flow structures in Racket using macros and continuations. Examples include:
return statement.
Advent of Code is a coding contest that takes place December 1st to 25th every year. Everyday a new puzzle is posted to the site. The puzzles form a larger story that is Christmas/Holiday themed. There is a global leaderboard which is pretty competitive. They also allow users to
| #lang racket | |
| (require json racket/draw math/base) | |
| (define (lat-lon->map-point coordinates) | |
| (match-define (list lon lat _ ...) coordinates) | |
| (define-values (x y) (values (degrees->radians lon) (asinh (tan (degrees->radians lat))))) | |
| (list (/ (+ 1 (/ x pi)) 2) (/ (- 1 (/ y pi)) 2))) | |
| (define (draw-polygon dc polygons) | |
| (define path |
| http://chronos-st.blogspot.com/2007/12/smalltalk-in-one-page.html | |
| http://www.csci.csusb.edu/dick/samples/smalltalk.syntax.html | |
| Formal EBNF Specification of Smalltalk Syntax | |
| 1. Character = ? Any Unicode character ?; | |
| 2. WhitespaceCharacter = ? Any space, newline or horizontal tab character ?; | |
| 3. DecimalDigit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"; | |
| 4. Letter = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M" | |
| | "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" |