dharmatech

Polymorphism in Scheme via compile time dispatch

Here's an example of polymorphism in C++:

int nth ( int a[] , int i ) { return a[i] ; }

double nth ( double a[] , int i ) { return a[i] ; }

One way to think of this is that there are two functions called nth. One can be called with an int array and the other can be called with a double array. The function that is called is determined at compile time by looking at the type of the expression of the first argument.

dharmatech

Generics in Scheme

In a previous note I demonstrated polymorphism in Scheme using Chez Scheme's compile time values and properties.

The code in that example is pretty raw; you might not want to code each generic in that manner. One approach is to decouple the signature/method table. We can do this by factoring out some code into a 'make-generic' procedure:

(define (make-generic table)
  (lambda (stx)
 (lambda (lookup)

danlentz

;; http://sourceforge.net/tracker/index.php?func=detail&aid=1359066&group_id=1355&atid=101355
;; user-defined :allocation :hash

(defpackage #:hash-classes
  (:use #:common-lisp
        #+allegro #:clos
        #+clisp #:clos
        #+cmu #:clos-mop
        #+lispworks #:clos
        #+(and mcl (not openmcl)) #:mcl-mop

jackrusher

;;; skewer-coffee.el --- skewer support for live-interactive Coffeescript

(defun skewer-coffee-eval (coffee-code)
  "Requests the browser to evaluate a coffeescipt string."
  ;; XXX should escape double quote characters
  (skewer-eval (concat "CoffeeScript.eval(\""
                       (s-replace "\n" "\\n" (s-trim coffee-code))
                       "\");")
               #'skewer-post-minibuffer))

OrionReed

// 3D Dom viewer, copy-paste this into your console to visualise the DOM as a stack of solid blocks.
// You can also minify and save it as a bookmarklet (https://www.freecodecamp.org/news/what-are-bookmarklets/)
(() => {
  const SHOW_SIDES = false; // color sides of DOM nodes?
  const COLOR_SURFACE = true; // color tops of DOM nodes?
  const COLOR_RANDOM = false; // randomise color?
  const COLOR_HUE = 190; // hue in HSL (https://hslpicker.com)
  const MAX_ROTATION = 180; // set to 360 to rotate all the way round
  const THICKNESS = 20; // thickness of layers
  const DISTANCE = 10000; // ¯\\_(ツ)_/¯