Glorp

#lang racket
(provide (rename-out (module-begin #%module-begin))
         #%app)

(define (push stack x)
  (cons x stack))

(define (add stack)
  (match stack
    [(list b a xs ...) (cons (+ a b) xs)]))

Glorp

-module(goats).
-compile(export_all).

cell(Pos, Vis) ->
	receive
		{neighbours, Cells} -> setupDeadCell(Pos, Cells, 0, Vis);
		Stuff -> io:format("cell, ~p~n", [Stuff]), false = true
	end.

setupDeadCell(Pos, Neighbours, AliveNeighbours, Vis) ->

Glorp

Syntax:
Exp u ::= x         variable
          λx.u      λ-abstraction
          u1 u2     application

Computation rule:
(λx.u2) u1
[u1/x]u2

0 := λf.λx.x

Glorp

#lang racket

(define (chars n)
  (string->list (~a n #:min-width 6 #:pad-string "0")))

(define (char->str c)
  (match c
    [#\0 "((((((("]
    [#\1 "(((((("]
    [#\2 "((((("]

Glorp

#lang racket
(require (only-in racket
                  (+ old+)))

(define (dechurch n)
  (n (λ (i) (old+ i 1)) 0))

(define (zero f x)
  x)

Glorp

#lang racket
(require (except-in 2htdp/universe left right)
         2htdp/image)

(struct pos (x y) #:transparent)
(struct ant (pos dir) #:transparent)
(struct world (ant grid mode count) #:transparent)

(define freq 20)

Glorp

#lang racket
(require (except-in 2htdp/universe left right up down)
         2htdp/image
         lang/posn
         (only-in racket (struct struckt)))

(define-syntax-rule (struct (name params ...))
  (struckt name (params ...) #:transparent))

;; column vector for position in 3D space

Glorp

(slide "start")
------------------------------------------------------------
Existential Lambda Calculus
or: Less Unitype, More Unicode

(start-lamb "C-e"
            "C-k"
            "C-S-d")
Standard ML of New Jersey v110.76 [built: Sun Jul 14 09:59:19 2013]
-

Glorp

datatype exp = Num of int
             | Plus of exp * int
             | Minus of exp * int

fun eval (Num n) = n 
  | eval (Plus (a, b)) = eval a + b
  | eval (Minus (a, b)) = eval a - b

fun expstr (Num n) = Int.toString n
  | expstr (Plus (a, b)) = expstr a ^ "+" ^ Int.toString b

Glorp

#lang racket
(define (evalexp e [n (+ (length e) 1)])
  (match e
    [`(|| . ,xs) (evalexp xs (string->number (~a (length e) n)))]
    [`(,x . ,xs) ((hash-ref (hash '+ + '- -) x) (evalexp xs) n)]
    [`() n]))

(define (perms len elms)
  (foldr (λ (_ res) (append-map (λ (p) (map (λ (e) `(,e . ,p)) elms)) res))
         '(())