内包表記(仮)

すごい合同勉強会の発表資料です。
https://github.com/LTDD/Sessions/wiki/%E3%81%99%E3%81%94%E3%81%84%E5%90%88%E5%90%8C%E5%8B%89%E5%BC%B7%E4%BC%9A2014

http://blog.eiel.info/blog/2014/11/02/internal-definitia-great-study/

Transcript

1. ಺แදه(Ծ) 2014-11-01 ͍͢͝߹ಉษڧձ
2. ͻΉΒ ͱ΋ͻ͜ GitHub eiel Hiλoshima Hiroshima.rb ޿ౡEmacsษڧձ http://nemca.net/
3. 10݄ͷπΠʔτ https://twitter.com/eielh/status/517681959837761536
4. ࠓ೔͸໨৽͍͜͠ͱ͸஻Βͳ͍
5. ಺แදه
6. ಺แදه ͱݺ͹ΕΔ΋ͷ͕͋ΔΒ͍͠ݴޠ • Python • Erlang • Scala • JavaScript 1.7 • Haskell
7. ྫ ۝۝Ͱ݁Ռ͕24ʹͳΔ΋ͷ
8. Python [(x,y) for x in range(1,10) for y in range(1,10) if x * y == 24 ] [(3, 8), (4, 6), (6, 4), (8, 3)]
9. ֎Ԇͱ಺แ
10. (ͪΐͬͱ਺ֶ) ू߹ͷهड़ํ๏
11. ೋͭͷه๏ ֎Ԇతه๏(extension definition) ۩ମతʹॻ͘ ಺แతه๏(intensional definition) ੑ࣭Λॻ͘
12. ۩ମྫ 10ະຬͷਖ਼ͷح਺ ֎Ԇ { 1, 3, 5, 7, 9} ಺แ { x | x ͸ 10ະຬͷਖ਼ͷح਺ } { x | x ∈ ℕ, x < 10, x % 2 = 1 }
13. ҰͭҰͭฒ΂ͨ͘ͳ͍
14. ͳΜΒ͔ͷ๏ଇ͕͋Δ
15. ಺แදهΛ࢖͏
16. Haskell 10ະຬͷਖ਼ͷح਺ [ x | x <- [1..9], x `mod` 2 == 1 ]
17. ࣅͯΔʁ ू߹ { x | x ∈ ℕ, x < 10, x % 2 = 1 } Haskell [ x | x <- [1..9], x `mod` 2 == 1 ]
18. ࣅͯΔʁ ू߹ { x | x ∈ ℕ, x < 10, x % 2 = 1 } Haskell [ x | x <- [1..9], x `mod` 2 == 1 ]
19. ࣅͯΔʁ ू߹ { x | x ∈ ℕ, x < 10, x % 2 = 1 } Haskell [ x | x <- [1..9], x `mod` 2 == 1 ]
20. ࣅͯΔʁ ू߹ { x | x ∈ ℕ, x < 10, x % 2 = 1 } Haskell [ x | x <- [1..9], x `mod` 2 == 1 ]
21. ࣅͯΔʁ ू߹ { x | x ∈ ℕ, x < 10, x % 2 = 1 } Haskell [ x | x <- [1..9], x `mod` 2 == 1 ]
22. ∈ <-
23. ऄ଍ ӳޠͩͱ Ϧετͷ಺แදه list comprehension ಺แతه๏ intensional definition
24. ಺แදهͷಡΈํ
25. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] [(3, 8), (4, 6), (6, 4), (8, 3)]
26. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] [(3, 8), (4, 6), (6, 4), (8, 3)] ݸͷϦετ
27. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] [(3, 8), (4, 6), (6, 4), (8, 3)] ݸͷϦετ ݸͷϦετ
28. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] [(3, 8), (4, 6), (6, 4), (8, 3)] ݸͷϦετ ݸͷϦετ 
    ௚ੵ
    
29. ௚ੵ 81ݸͷϦετ [(x,y) | x <- [1..9], y <- [1..9]] [(1,1),(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8),(1,9), (2,1),(2,2),(2,3),(2,4),(2,5),(2,6),(2,7),(2,8),(2,9), (3,1),(3,2),(3,3),(3,4),(3,5),(3,6),(3,7),(3,8),(3,9), (4,1),(4,2),(4,3),(4,4),(4,5),(4,6),(4,7),(4,8),(4,9), (5,1),(5,2),(5,3),(5,4),(5,5),(5,6),(5,7),(5,8),(5,9), (6,1),(6,2),(6,3),(6,4),(6,5),(6,6),(6,7),(6,8),(6,9), (7,1),(7,2),(7,3),(7,4),(7,5),(7,6),(7,7),(7,8),(7,9), (8,1),(8,2),(8,3),(8,4),(8,5),(8,6),(8,7),(8,8),(8,9), (9,1),(9,2),(9,3),(9,4),(9,5),(9,6),(9,7),(9,8),(9,9)]
30. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] [(3, 8), (4, 6), (6, 4), (8, 3)] ݸͷϦετ ݸͷϦετ 
    ௚ੵ
     ʹͳΔ΋ͷ͚ͩʹ͢Δ
31. Python [(x,y) for x in range(1,10) for y in range(1,10) if x * y == 24 ] [(3, 8), (4, 6), (6, 4), (8, 3)] ݸͷϦετ ݸͷϦετ 
    ௚ੵ
     ʹͳΔ΋ͷ͚ͩʹ͢Δ
32. ಺แදهͬͯศརͳΜʁ
33. –Python νϡʔτϦΞϧ “Ϧετͷ಺แදه (list comprehension) ͸ɺ map() ΍ filter() ΍ lambda Λ࢖ΘͣʹϦετ Λੜ੒͢ΔͨΊͷ؆ܿͳํ๏Λఏڙ͍ͯ͠· ͢ɻ಺แදهʹΑΔϦετͷఆٛ͸ɺ͍ͨͯ ͍ map(), filter(), lambda Λ࢖ͬͯϦετΛੜ ੒͢ΔίʔυΑΓ΋໌շʹͳΓ·͢ɻ”
34. Ruby [*1..9].map do |x| [*1..9].map do |y| [x,y] end end.flatten(1).select do |x,y| x * y == 24 end
35. ͋ͬ…͏Μ
36. 3ͭͷੵ͕24
37. Haskell [(x,y,z) | x <- [1..9], y <- [1..9], z <- [1..9], x * y * z == 24]
38. Ruby [*1..9].map do |x| [*1..9].map do |y| [*1..9].map do |z| [x,y,z] end end end.flatten(2).select do |x,y,z| x * y * z == 24 end
39. ࣼΊʹ৳ͼΔ… ͳʹ͜Επϥ͍
40. ऄ଍ ࣼΊʹ৳ͼΔίʔυ ඇಉظॲཧ nodejs ίʔϧόοΫ஍ࠈ
41. map Ͱ΍Ζ͏ͱ͢Δ͔Β ͓͔͘͠ͳΔ
42. ௚ੵ͢Ε͹͍͍
43. Ruby [*1..9] .product([*1..9],[*1..9]) .select do |x,y,z| x * y * z == 24 end
44. ͜ΕͳΒ࢖͑Δ
45. ू߹ͱ͍͑͹
46. σʔλϕʔε
47. ಺แදهͱSQL
48. in PosgreSQL SELECT x,y FROM generate_series(1,9) AS X, generate_series(1,9) AS Y WHERE x * y = 24;
49. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24]
50. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] TFMFDU
51. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] TFMFDU GSPN
52. Haskell [(x,y) | x <- [1..9], y <- [1..9], x * y == 24] TFMFDU GSPN XIFSF
53. ͦͬ͘Γ
54. ΋͏಺แදهා͘ͳ͍
55. SQLͬΆ͔ͭ͑͘Δ?
56. ҰൠԽ(SQL෩) Ϧετ಺แදه
57. LIMIT :set -XTransformListComp [ (x,y) | x <- [1..9], y <- [1..9], x * y == 24, then take 2] [(3, 8), (4, 6)]
58. ORDER :set -XTransformListComp :m GHC.Exts [ (x,y) | x <- [1..9], y <- [1..9], x * y == 24, then sortWith by y] [(8, 3) (6, 4), (4, 6), (3, 8)]
59. GROUPͱ͔লུ
60. ͱ͜ΖͰ Ϟφυ
61. ϞφυͰ΋Ͱ͖ΔΑ do x <- [1..9] y <- [1..9] guard (x * y == 24) return (x,y) [(3, 8), (4, 6), (6, 4), (8, 3)]
62. ϞφυͰ΋Ͱ͖ΔΑ do x <- [1..9] y <- [1..9] guard (x * y == 24) return (x,y) TFMFDU [(3, 8), (4, 6), (6, 4), (8, 3)]
63. ϞφυͰ΋Ͱ͖ΔΑ do x <- [1..9] y <- [1..9] guard (x * y == 24) return (x,y) GSPN TFMFDU [(3, 8), (4, 6), (6, 4), (8, 3)]
64. ϞφυͰ΋Ͱ͖ΔΑ do x <- [1..9] y <- [1..9] guard (x * y == 24) return (x,y) XIFSF GSPN TFMFDU [(3, 8), (4, 6), (6, 4), (8, 3)]
65. ͦͬ͘ΓͰ͢Ͷ
66. ϞφυͳΒ ϦετҎ֎΋͋ΔΑͶ
67. Maybe do x <- Just 3 y <- Just 8 guard (x * y == 24) return (x,y) Just (3,8)
68. Maybe do x <- Just 3 y <- Just 8 guard (x * y == 25) return (x,y) Nothing
69. Maybeͷ಺แදه
70. Maybeͷ಺แදه :set -XMonadComprehensions [ (x,y) | x <- Just 3, y <- Just 8, x * y == 24]
71. Ϟφυͷ಺แදه
72. ·ͱΊ
73. ·ͱΊ ֎Ԇ - શ෦ฒ΂Δ ಺แ - ੑ࣭Ͱදݱ ಺แදهͱSQL͕ࣅͯΔͬΆ͍ ϦετҎ֎ͷ಺แදه͕͋Δ
74. Ϟφυා͘ͳͦ͞͏
75. ͝ਗ਼ௌ͋Γ͕ͱ͏͍͝͞·ͨ͠