Lisp (laraconeu)

Transcript

3. Computers
4. What are they even?
5. @igorwhiletrue
6. A little history
7. brb inventing programming
8. computers they’re so great <3 Alonzo Church
10. John McCarthy
11. I <3 computers but hate assembly language
14. (
16. ( ) parentheses are hugs
17. ❤ ( )
18. How to read lisp code, in one easy step
19. foo(1, 2)
20. (foo 1 2)
21. (+ 1 2)
23. Growing a language
24. a bar foo atom
26. cons
27. first
28. rest
29. a b
30. (a . b)
31. a
32. (a . nil)
33. a b c
34. (a . (b . (c . nil)))
35. (a b c)
36. (foo (bar) (baz qux))
37. foo bar baz qux
38. foo(bar(), baz(qux))
39. foo bar baz qux fn arg 0 arg 1 fn fn arg 0 call call call
40. (foo (bar) (baz qux))
41. (foo (bar) (baz qux)) fn arg 0 arg 1
42. (foo (bar) (baz qux)) fn arg 0 fn
43. (quote (a b c))
44. '(a b c)
45. (first '(a b c)) !
46. (first '(a b c)) ! 'a
47. a b c
48. (rest '(a b c)) !
49. (rest '(a b c)) ! '(b c)
50. a b c
51. (cons 'a '(b c)) !
52. (cons 'a '(b c)) ! '(a b c)
53. a b c
54. 5 3.14 "fubar" variable :keyword
55. (fn [x] x)
56. (fn [x] x) arguments
57. (fn [x] x) body
58. (def answer 42)
59. (def hello (fn [name] (str "Hello " name)))
60. (hello “Laracon”)
61. No loops
62. Recursive functions
63. in order to understand rec ursion, one must first understand re cursion,
64. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
65. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
66. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
67. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
68. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
69. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
70. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
71. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll)))))
72. (member? 'c '(a b c d))
73. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) ! (member? 'c '(a b c d))
74. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) ! (member? 'c '(a b c d))
75. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) ! (member? 'c '(a b c d))
76. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) ! (member? 'c '(a b c d))
77. (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))
78. (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))
79. (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))
80. (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))
81. (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))
82. (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))
83. (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))
84. (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
85. (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
86. (defn member? [x coll] (cond (empty? coll) false :else (or (= (first coll) x) (member? x (rest coll))))) ! (member? 'c '(a b c d)) => true
87. true
88. Macros
89. (foo (bar) (baz qux))
90. "(+ 1 2)" Reader + 1 2 + 1 2 Eval 3 Compile-time Runtime x 0 y 1 z 2
91. "(a 1 2)" Reader a 1 2 Compile-time Macro b 5 6 a 1 2
92. (defn id [x] x) ! (def id (fn [x] x)) =>
93. (-> '(foo bar baz) reverse first name string/reverse) (string/reverse (name (first (reverse '(foo bar baz)))) =>
94. class Foo ($bar) { } class Foo { private $bar; function __construct($bar) { $this->bar = $bar; } } =>
95. Backporting?
96. function () use ($foo) { return qux($foo); } => () ==> qux($foo)
97. hhvm 5.6 5.5 5.4 FI ...
98. Computer Science
99. Computer Science
100. Computer Science
101. Y-Combinator
102. (defn Y [le] ((fn [f] (f f)) (fn [f] (le #((f f) %)))))
103. (defn fac [f] (fn [x] (if (zero? x) 1 (* x (f (dec x))))))
104. ((Y fac) 5)
105. ((Y ) 5) (fn [f] (fn [x] (if (zero? x) 1 (* x (f (dec x))))))
106. (( ) 5) (fn [f] (fn [x] (if (zero? x) 1 (* x (f (dec x)))))) (fn [le] ((fn [f] (f f)) (fn [f] (le #((f f) %)))))
107. Lambda Calculus
108. 0: (fn [f] identity) 1: (fn [f] f) 2: (fn [f] #(f (f %))) 3: (fn [f] #(f (f (f %))))
109. ((n inc) 0)
110. (( inc) 0) (fn [f] identity)
111. ( 0) identity
113. (( inc) 0) (fn [f] f)
114. ( 0) inc
116. (( inc) 0) (fn [f] #(f (f %)))
117. ( 0) #(inc (inc %))
119. (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)))
120. Meta-circular
     evaluator
121. (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)))))
122. 62 LOC
123. function evaluate($expr, $env = []) { if (is_string($expr)) { if (is_numeric($expr)) { $val = (float) $expr; return [$val, $env]; } if ('true' === $expr) { return [true, $env]; } if ('false' === $expr) { return [false, $env]; } if ('null' === $expr) { return [null, $env]; } $var = $expr; return [$env[$var], $env]; } $fn = array_shift($expr); $args = $expr; if ('define' === $fn) { list($var, $val) = $args; list($val, $env) = evaluate($val, $env); $env = array_merge($env, [$var => $val]); return [null, $env]; } if ('lambda' === $fn) { list($lambda_args, $code) = $args; $closure = ['closure', $lambda_args, $code, $env]; return [$closure, $env]; } if ('if' === $fn) { list($cond, $then, $else) = $args; $cond = evaluate($cond, $env)[0]; if ($cond === true) { $val = evaluate($then, $env)[0]; } else { $val = evaluate($else, $env)[0]; } return [$val, $env]; } ! $fn = evaluate($fn, $env)[0]; $args = array_map(function ($arg) use ($env) { return evaluate($arg, $env)[0]; }, $args); return apply($fn, $args, $env); } ! function apply($fn, $args, $env) { list($_, $lambda_args, $code, $closure_env) = $fn; ! $env = array_merge($env, $closure_env); $env = array_merge($env, array_combine($lambda_args, $args)); return evaluate_code($code, $env); } function evaluate_code($code, $env = []) { foreach ($code as $expr) { list($val, $env) = evaluate($expr, $env); } return [$val, $env]; }
124. 68 LOC
125. PHPPHP: 6208 LOC github.com/ircmaxell/PHPPHP
126. PHPPHP: 6208 LOC github.com/ircmaxell/PHPPHP (parser +6169 LOC)
127. )
132. Questions? • joind.in/11697 • github.com/igorw • lambda-php • lusp • ilias • galapagos • @igorwhiletrue
134. References • Lisp Logo by Conrad Barski
 lisperati.com/logo.html • Jesus bleibet meine Freude by Jeffrey Campbell • Programming with Nothing by Tom Stuart
 codon.com/programming-with-nothing • The Magnificent Seven by Michael Fogus
 fogus.me/static/preso/magnificent7/
135. • Recursive functions of symbolic expressions and their computation by machine, Part I by John McCarthy
 www-formal.stanford.edu/jmc/recursive.pdf • Growing a Language by Guy Steele
 youtube.com/watch?v=_ahvzDzKdB0 • The Lambda Papers by Guy Steele and Gerald Sussman
 library.readscheme.org/page1.html • SICP lectures by Hal Abelson and Gerald Sussman
 groups.csail.mit.edu/mac/classes/6.001/abelson- sussman-lectures/