Introduction to Lisp (dpc13)

Transcript

1. Introduction to
2. @igorwesome
3. (
4. John McCarthy
6. f o r g e t everything y o u k n o w
7. (+ 1 2)
8. (+ 1 2) l i s t
9. (+ 1 2) symbol
10. (+ 1 2) number
11. (+ 1 2) number
12. (+ 1 2) a p p l i c a t i o n
13. (+ 1 2) function
14. (+ 1 2) arguments
17. cons
18. car
19. first
20. cdr
21. rest
22. (a . b)
23. a b
24. (a . nil)
25. a
26. (a . (b . (c . nil)))
27. a b c
28. (a b c)
29. [:a :b :c]
30. (first [:a :b :c])
31. (first [:a :b :c]) :a
32. a b c
33. (rest [:a :b :c])
34. (rest [:a :b :c]) [:b :c]
35. a b c
36. (cons :a [:b :c])
37. (cons :a [:b :c]) [:a :b :c]
38. a b c
39. (+ 2 3 5 7 11 13)
40. (/ (+ (- b) (math.sqrt (- (math.expt b 2) (* 4 a c)))) (* 2 a)) (/ (- (- b) (math.sqrt (- (math.expt b 2) (* 4 a c)))) (* 2 a))
41. 5 3.14 "fubar" variable :keyword
42. (fn [x] x)
43. (fn [x] x) arguments
44. (fn [x] x) body
45. (def answer 42)
46. (def hello (fn [name] (str "Hello " name)))
47. (defn hello [name] (str "Hello " name))
48. (hello "dpc13")
49. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
50. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
51. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
52. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
53. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
54. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
55. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
56. (member? :c [:a :b :c :d])
57. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d])
58. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d])
59. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d])
60. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d])
61. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d])
62. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d])
63. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d])
64. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d])
65. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d]) (member? :c [:c :d])
66. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d]) (member? :c [:c :d])
67. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d]) (member? :c [:c :d])
68. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d]) (member? :c [:c :d]) => true
69. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) (member? :c [:b :c :d]) => true
70. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) (member? :c [:a :b :c :d]) => true
71. true
72. Collections
73. Filter
74. 0 1 2 3 4 even?
75. 0 1 2 3 4 even? 0
76. 0 1 2 3 4 even? 0
77. 0 1 2 3 4 even? 0 2
78. 0 1 2 3 4 even? 0 2
79. 0 1 2 3 4 even? 0 2 4
80. (filter even? [0 1 2 3 4])
81. Map
82. 0 1 2 3 4 #(+ 5 %)
83. 0 1 2 3 4 #(+ 5 %) 5
84. 0 1 2 3 4 #(+ 5 %) 5 6
85. 0 1 2 3 4 #(+ 5 %) 5 7 6
86. 0 1 2 3 4 #(+ 5 %) 5 7 6 8
87. 0 1 2 3 4 #(+ 5 %) 5 7 9 6 8
88. (map #(+ 5 %) [0 1 2 3 4])
89. Reduce
90. 3 6 7 9 + 0 running total
91. 3 6 7 9 + 0 3 running total
92. 3 6 7 9 + 0 9 3 running total
93. 3 6 7 9 + 0 9 3 16 running total
94. 3 6 7 9 + 0 9 25 3 16 running total
95. 3 6 7 9 + 0 9 25 3 16 running total
96. (reduce + 0 [3 6 7 9])
97. 0 1 2 3 4 even? 0 2 4 #(+ 5 %) 5 7 9 + 5 12 21
98. Macros
99. (foo bar baz)
100. "(+ 1 2)" Reader + 1 2 + 1 2 Eval 3 Compile-time Runtime x 0 y 1 z 2
101. "(a 1 2)" Reader a 1 2 Compile-time Macro b 5 6 a 1 2
102. (defn id [x] x) => (def id (clojure.core/fn ([x] x)))
103. (-> [:foo :bar :baz] reverse first name string/reverse) (string/reverse (name (first (reverse [:foo :bar :baz])))) =>
104. (defmacro unless [pred a b] `(if (not ~pred) ~a ~b))
105. (unless foo x y) => (if (not foo) x y)
106. unless ($foo) => if (!$foo)
107. retry (5) { failing_call(); } catch ($e) { // ... whoops }
108. class Foo ($bar) { } => class Foo { private $bar; function __construct($bar) { $this->bar = $bar; } }
109. ($x): $x => fn ($x) { return $x; } => function ($x) { return $x; }
110. Y-Combinator
111. (defn Y [le] ((fn [f] (f f)) (fn [f] (le #((f f) %)))))
112. (defn fac [f] (fn [x] (if (zero? x) 1 (* x (f (dec x))))))
113. ((Y fac) 5)
114. ((Y ) 5) (fn [f] (fn [x] (if (zero? x) 1 (* x (f (dec x))))))
115. (( ) 5) (fn [f] (fn [x] (if (zero? x) 1 (* x (f (dec x)))))) (fn [le] ((fn [f] (f f)) (fn [f] (le #((f f) %)))))
116. Lambda Calculus
117. 0: (fn [f] identity) 1: (fn [f] f) 2: (fn [f] #(f (f %))) 3: (fn [f] #(f (f (f %))))
118. ((n inc) 0)
119. (( inc) 0) (fn [f] identity)
120. ( 0) identity
122. (( inc) 0) (fn [f] f)
123. ( 0) inc
125. (( inc) 0) (fn [f] #(f (f %)))
126. ( 0) #(inc (inc %))
128. (defn INC [n] (fn [p] (fn [x] (p ((n p) x))))) (defn DEC [n] (fn [f] (fn [x] (((n (fn [g] (fn [h] (h (g f))))) (fn [y] x)) (fn [y] y))))) (defn ADD [m] (fn [n] ((n INC) m))) (defn MUL [m] (fn [n] ((n (ADD m)) ZERO)))
129. Meta-circular evaluator
130. • = • fn • cond • cons • first • rest • quote
131. (defun null. (x) (eq x '())) (defun and. (x y) (cond (x (cond (y 't) ('t '()))) ('t '()))) (defun not. (x) (cond (x '()) ('t 't))) (defun append. (x y) (cond ((null. x) y) ('t (cons (car x) (append. (cdr x) y))))) (defun list. (x y) (cons x (cons y '()))) (defun pair. (x y) (cond ((and. (null. x) (null. y)) '()) ((and. (not. (atom x)) (not. (atom y))) (cons (list. (car x) (car y)) (pair. (cdr x) (cdr y)))))) (defun assoc. (x y) (cond ((eq (caar y) x) (cadar y)) ('t (assoc. x (cdr y))))) (defun eval. (e a) (cond ((atom e) (assoc. e a)) ((atom (car e)) (cond ((eq (car e) 'quote) (cadr e)) ((eq (car e) 'atom) (atom (eval. (cadr e) a))) ((eq (car e) 'eq) (eq (eval. (cadr e) a) (eval. (caddr e) a))) ((eq (car e) 'car) (car (eval. (cadr e) a))) ((eq (car e) 'cdr) (cdr (eval. (cadr e) a))) ((eq (car e) 'cons) (cons (eval. (cadr e) a) (eval. (caddr e) a))) ((eq (car e) 'cond) (evcon. (cdr e) a)) ('t (eval. (cons (assoc. (car e) a) (cdr e)) a)))) ((eq (caar e) 'label) (eval. (cons (caddar e) (cdr e)) (cons (list. (cadar e) (car e)) a))) ((eq (caar e) 'lambda) (eval. (caddar e) (append. (pair. (cadar e) (evlis. (cdr e) a)) a))))) (defun evcon. (c a) (cond ((eval. (caar c) a) (eval. (cadar c) a)) ('t (evcon. (cdr c) a)))) (defun evlis. (m a) (cond ((null. m) '()) ('t (cons (eval. (car m) a) (evlis. (cdr m) a)))))
132. 62 LOC
133. PHPPHP: 6208 LOC github.com/ircmaxell/PHPPHP After lunch, E102
134. PHPPHP: 6208 LOC github.com/ircmaxell/PHPPHP After lunch, E102 (parser +6169 LOC)
135. )
139. • www.lisperati.com/logo.html • codon.com/programming-with-nothing • fogus.me/static/preso/magnificent7/
140. Questions? • joind.in/8442 • clojure.org • @igorwesome