florence

#lang racket
(require redex)

(current-cache-all? #t)

(define-language L
  (e x t f (e ∧ e) (e ∨ e) (¬ e) (e → e))
  (x variable-not-otherwise-mentioned))

(define-extended-language LC L

florence

#lang at-exp slideshow
(require slideshow/code racket/draw)

(define (red t)
  (color "darkmagenta" t))
(define (green t)
  (color "olive" t))
(define (blue t)
  (color "royalblue" t))
(define (color c t)

florence

#lang racket
(define ns (make-base-namespace))
(namespace-attach-module (current-namespace) ''#%builtin ns)

(define args (contract (vectorof string?) (vector "a") 'pos 'neg))

(parameterize ([current-namespace ns])
  (define current-args
    (namespace-variable-value 'current-command-line-arguments ns))
  (parameterize ([current-args args])

florence

#lang typed/racket

(require pict3d)

(: aprox-mandel : (Natural -> (Dir -> Dir)))
(define ((aprox-mandel n) c)
  (define Z (mandel c))
  (let loop : Dir ([n : Natural n] [z_n : Dir zero-dir])
       (if (zero? n)
           (Z z_n)

florence

(define-expander-type ppict-ext)

(begin-for-syntax
  (define-syntax-class ppict-body
    #:datum-literals (splice)
    #:attributes ((flatten 1))
    (pattern (splice a:ppict-body ...)
             #:attr (flatten 1)
             (syntax->list #'(a.flatten ... ...)))
    (pattern a

florence

#lang racket
(require parser-tools/lex
         (prefix-in : parser-tools/lex-sre))

(define-lex-trans ::? 
  (lambda (stx)
    (syntax-case stx ()
      [(_ v b)
       #'(:: v (:? " ") b)])))

florence

#lang racket
(require redex)
(define-language SKI
  (e ::= S K I (e e) natural +))
(define R
  (reduction-relation
   SKI
   (--> (((S e_1) e_2) e_3)
        ((e_1 e_3) (e_2 e_3)))
   (--> ((K e_1) e_2) e_1)

florence

#lang racket
(require data/enumerate)
(require data/enumerate/lib)
(require racket/draw)
(require pict)

;; adjust byte size to shrink the range of colors
(define byte-size 256)
(define byte/e (below/e byte-size))
(define (byte->actual x)

florence

#lang scribble/doc

Okay, we've made a package and up loaded. But you know what would be lovely?.
Docs! This tutorial is going to start assuming you have a blank file and now clue where to start. By
the end we will have written the documentation for this line-of-best-fit library <show>.

This is racket land, so of course we have a language for documentation! #lang scribble/doc


@(require scribble/manual

florence

import java.lang.reflect.*;
import sun.misc.Unsafe;

public class Print {

   static Unsafe u = getUnsafe();

   public static void main(String... args) {
      try {
         long addr = u.staticFieldOffset(System.class.getDeclaredField("err")) +4;