samth

#lang racket

(struct proc/prop (f v)
  #:property prop:procedure 0)

(define (procedure-property p [fail #f])
  (if (proc/prop? p)
      (proc/prop-v p)
      fail))

samth

#lang racket
(require racket/generator
         rackunit
         rackunit/text-ui)

(define/contract (group seq group-size)
  (sequence? natural-number/c . -> . sequence?)
  (in-generator
   (let-values ([(l final-chunk)
                 (for/fold ([l 0] [this-chunk null])

samth

Welcome to Racket v5.1.1.6.
> (time (for/first ([i (in-naturals 1)] 
                    #:when (regexp-match #rx"^(1|0)*$"
                                         (number->string (* i 225))))
          (* i 225)))
cpu time: 53687 real time: 53692 gc time: 1072
11111111100
> 

samth

#lang racket 
(require unstable/dict)
(provide main)

;; Set[String]
(define stopwords (list->set (file->lines "./stopwords.txt")))

;; String -> List[String]
(define (tokenize raw-text) ;; Lowercases and splits on non-letters, non-numbers.
  (filter-not (λ (e) (set-member? stopwords e)) 

samth

#lang at-exp racket
(define str
@string-append||{
;; giant wall of characters goes here
}||)

(define (frequencies l)
  (for/fold ([h (hash)]) ([i l]) (hash-update h i add1 0)))
(define h (frequencies str))
(apply string

samth

#lang racket/base

;; translated from an algorithm in C from
;; Hyberts SG, Takeuchi K, Wagner G (2010) Poisson-gap sampling and
;; forward maximum entropy reconstruction for enhancing the resolution
;; and sensitivity of protein NMR Data. J Am Chem Soc 132:2145–2147

;; generate random Poisson-distributed numbers as given
;; by Donald E. Knuth (1969). Seminumerical Algorithms.
;; The Art of Computer Programming, Volume 2. Addison Wesley

samth

#lang typed/racket

(: stx Syntax)
(define stx #'bar)

(syntax-case stx () 
  [foo (identifier? #'foo) (symbol=? 'bar (syntax-e #'foo))]
  [_ (error 'whoops)])

samth

#lang typed/racket

(define-syntax (cond* stx)
  (syntax-case stx ()
    [(_ x clause ...)
     #`(cond clause ... [else (typecheck-fail #,stx "incomplete coverage" #:covered-id x)])]))

(: f : (U String Integer) -> Boolean)
(define (f x)
  (cond* x

samth

#lang racket

#reader"read-eval.rkt"
(begin 
  #.(begin (define x 30) '(void))
  '(1 2 #.x))

samth

#lang racket
(require syntax/parse/define)
(define-simple-macro (def (f0:id p0 ...) rhs0:expr (~seq (f:id p ...) rhs:expr) ...)
  (define f0 (match-lambda** [(p0 ...) rhs0] [(p ...) rhs] ...)))

(def (fact 0) 1 (fact 1) 1 (fact n) (* n (fact (- n 1))))

(fact 5)