dyoo

#lang racket/base

;; Unfriendly numbers
;; https://www.interviewstreet.com/challenges/dashboard/#problem/4f7272a8b9d15

;; We'll provide a single function to solve this problem.
;;
;; Note that this module itself can be run as a main program, due to the
;; "main" submodule at the bottom of this file.
;;

dyoo

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

(define (do-the-build)
  (define f (new frame% [label "Building..."]))
  (define t (new text% [auto-wrap #t]))
  (define c (new editor-canvas% [parent f] [editor t]))
  (send f show #t)
  (void (thread (lambda ()

dyoo

#lang racket/base

;; http://en.wikipedia.org/wiki/Machine_epsilon
;; approximates the machine epsilon

(require racket/flonum)
(define (compute-machine-epsilon)
  (let loop ([n 1.0])
    (define new-n (fl/ n 2.0))
    (cond

dyoo

#lang racket

;; Let's create a custom structure for procedures that remember certain things.
(struct proc/data (proc data)
  #:property prop:procedure (lambda (pd . args)
                              (apply (proc/data-proc pd) args)))

;; We can manually create such instances...
(define f (proc/data 
           ;; implementation:

dyoo

#lang racket

;; http://stackoverflow.com/questions/12345647/rewrite-this-script-by-designing-an-interpreter-in-racket

;; A pexpr is one of the following:
;;   * a primitive string,
;;   * a seq, or
;;   * a repeat
(struct seq (bodies) #:transparent)
(struct repeat (n body) #:transparent)

dyoo

#lang racket

(require rackunit
         (for-syntax racket/syntax))

;Records - like structs but less ugly and much less efficient
(define-syntax (record stx)
  (syntax-case stx ()
    [(_ name slots ...)
     (with-syntax ([new-name (format-id #'name "new-~a" (syntax-e #'name))])

dyoo

#lang racket/base
(require racket/stream)


;; decimal-to-binary-fraction: positive-real-less-than-1 -> (sequenceof (U 0 1))
;; Computes the binary expansion of the fraction part of a number.
(define (decimal-to-binary-fraction n)
  (let loop ([n n]
             [current-fraction 1/2])
    (cond [(= n 0)

dyoo

#lang racket
(require racket/generator)

(define-syntax (for/seq stx)
  (syntax-case stx ()
    [(_ clauses . body)
     #`(in-generator
        (for/fold/derived #,stx
                          ()
                          clauses

dyoo

#lang racket


;; http://www.cforcoding.com/2012/01/interview-programming-problems-done.html

;; A little syntax for memoizing functions like Pascal's triangle.
(define-syntax (define/memo stx)
  (syntax-case stx ()
    [(_ (name args ...) body ...)
     (syntax/loc stx 

dyoo

#lang racket

;; Counts words, treating tilde-words as escaped words.
;; Based on the SO question:
;;
;; http://stackoverflow.com/questions/12666553/efficient-word-count-method-using-regex-or-something


(require rackunit)