Metaxal

#lang racket
(require framework
         racket/gui/base)

(provide theme->frame)

; Call (theme->frame) to open a frame with the current style as an info.rkt file

(color-prefs:register-info-based-color-schemes)

Metaxal

#lang slideshow
(require bazaar/slideshow/slideshow-tree)

(define t1 '(a (b1 (c1 d1 d2) 
                   (c2 d3 d4)) 
               (b2 (c3 d5) 
                   c4)))

(draw-tree-top-left-right 
 (tree-map t1 (λ(x)(t (symbol->string x))))

Metaxal

#lang racket
(require measures)

(define-syntax-rule (define-units-contract name m1)
  (define name
         (make-flat-contract
          #:name 'name
          #:first-order
          (λ(m2)(measure-units-equal? m1 m2)))))

Metaxal

#lang racket
(require (for-syntax racket/base
                     syntax/parse)
         racket/list
         racket/match)

;; Related post: http://jeapostrophe.github.io/2013-11-12-condd-post.html

(define (f-condd4 l)
  (condd4

Metaxal

(defn
  #:doc @list{Multiplies @racket[x] by @racket[y].
              Use it fruitfully.}
  #:ex [10 3 => 30]
  #:ex [0 3 => 0]
  #:ex [10 => 10]
  #:ex [0 => 0]
  ;; The function signature
  (mult [x number?][y number? 1] -> number?)
    ;; And the function body:

Metaxal

#lang racket

;;; Run this file with `racket test-big-bang.rkt`
;;; then type quickly "asdf" to trigger several successive to-draw events.
;;; Drawing the scene is fast, but rendering it on-screen is very slow?

(require 2htdp/image
         2htdp/planetcute
         2htdp/universe)

Metaxal

#!/usr/bin/python
# From: http://nbviewer.ipython.org/url/norvig.com/ipython/xkcd1313.ipynb
import re

def verify(regex, winners, losers):
    "Return true iff the regex matches all winners but no losers."
    missed_winners = {W for W in winners if not re.search(regex, W)}
    matched_losers = {L for L in losers if re.search(regex, L)}
    if missed_winners:
        print "Error: should match but did not:", ', '.join(missed_winners)

Metaxal

#lang racket

;; proc : procedure? ; procedure to apply
;; dict : dict? ; dictionary of keywords and values
;;     A key can be either a keyword or a symbol that is turned into a keyword.
;; largs : list? ; positional arguments
;; Returns the result of the application of proc to the positional arguments and the keyword values.
(define (keyword-apply/dict proc dict largs)
  (define alist
    (sort

Metaxal

#lang racket/gui

(define my-frame%
  (class frame%
    (define/override (on-subwindow-event receiver event)
      (when (send event button-down?)
        (displayln (send receiver get-label)))
      #f)
    (super-new)))

Metaxal

#lang racket/base

(require racket/gui/base
         racket/class
         racket/format)

(define NUM-CELL-X 100)
(define NUM-CELL-Y 100)
(define CELL-SIZE 2)
(define XMAX (* NUM-CELL-X CELL-SIZE))