静的型付け言語 Crystal

Tokyo Crystal Meetup #2 (2015-10-23)

Transcript

1. ੩తܕ෇͚ݴޠ
   $SZTUBM Crystal The Programming Language with Static Typing Hirofumi Wakasugi (@5t111111)
2. $SZTUBM͸੩తܕ෇͚ͷ
   ϓϩάϥϛϯάݴޠͰ͢ɻ
3. ੩తܕ෇͚ w ม਺ͳͲͷܕ͸ίϯύΠϧ࣌ʹܾఆ͞Ε͍ͯΔ
   w ܕνΣοΫʹΑͬͯࣄલʹόάΛัଊ͠΍͍͢ w ม਺ͳͲͷܕ͸࣮ࡍͷ࣮ߦ࣌ͷ஋ʹͳΔ
   w ॊೈͰ࠶ར༻ੑͷߴ͍ϓϩάϥϜΛॻ͖΍͍͢ ಈతܕ෇͚
4. ಈతܕ෇͚ͷ3VCZͱ
   ੩తܕ෇͚ͷ$SZTUBM
   Ͳ͕ͬͪ༏ΕͯΔ͔ͱ͔
   ͦ͏͍͏࿩͸͠·ͤΜʂ
5. $SZTUBM͕
   ੩తܕ෇͚ݴޠͱͯ͠
   ͲͷΑ͏ʹಇ͔͘
   ୶ʑͱݟ͍͖ͯ·͢ɻ
6. ม਺ͷఆٛ a = 3 b = "we are like crystal, we break easy" c = [1, 2, 3] w ม਺
   B
   ͷܕ͸
   *OU
   w ม਺
   C
   ͷܕ͸
   4USJOH
   w ม਺
   D
   ͷܕ͸
   "SSBZ *OU ม਺͸ॳΊͯ஋͕୅ೖ͞Εͨͱ͖ʹએݴ͞ΕΔ
7. ม਺ͷఆٛ w ม਺
   B
   ͷܕ͸
   *OU
   w ม਺
   C
   ͷܕ͸
   4USJOH
   w ม਺
   D
   ͷܕ͸
   "SSBZ *OU ม਺͸ॳΊͯ஋͕୅ೖ͞Εͨͱ͖ʹએݴ͞ΕΔ a = 3 b = "we are like crystal, we break easy" c = [1, 2, 3] ܕਪ࿦ 
 5ZQF
   *OGFSFODF

8. ม਺΁ͷ࠶୅ೖ ͜Ε͸Ͳ͏ͳΔʁ
   Τϥʔʹͳͬͯ͠·͏ͷʁ ͢Ͱʹએݴ͞Εͯܕ͕ܾ·͍ͬͯΔม਺ʹ୅ೖ͢Δ a = "we are like crystal, it is not easy" a = 100
9. ม਺΁ͷ࠶୅ೖ ผͷܕΛม਺ʹ୅ೖͯ͠΋Τϥʔʹ͸ͳΒͳ͍
   ม਺ͷܕ͸୅ೖ͞ΕΔࣜ
   ஋
   ʹΑͬͯܕਪ࿦͞ΕΔ ͢Ͱʹએݴ͞Εͯܕ͕ܾ·͍ͬͯΔม਺ʹ୅ೖ͢Δ a = "we are like crystal, it is not easy" # ここで変数 a は String a = 100 # ここで変数 a は Int32
10. "SSBZͷܕ ͜Ε͸Ͳ͏ͳΔʁ
    ͍͚ͦ͏͡Όͳ͍ʁ *OUͷ"SSBZʹ4USJOHܕͷཁૉΛ௥Ճ͢Δ a = [1, 2, 3] a << "we are like crystal"
11. "SSBZͷܕ *OUͷ"SSBZʹ4USJOHܕͷཁૉΛ௥Ճ͢Δ a = [1, 2, 3] a << "we are like crystal" no overload matches 'Array(Int32)#<<' with types String Overloads are: - Array(Int32)#<<(value : Int32) a << "we are like crystal" ^~ ͜Ε͸
    ίϯύΠϧΤϥʔ &SSPS
12. ۭͷ"SSBZ ܕΛࢦఆͤͣʹۭͷ"SSBZΛએݴ͢Δ͜ͱ͸Ͱ͖ͳ͍ a = [] # Syntax Error a = [] of Int32 # OK! ͱ͍͏͜ͱ͸ɺ
    ҟͳΔܕͷཁૉΛؚΉ"SSBZ͸
    ࡞Εͳ͍ʁ
13. 6OJPOܕ "SSBZ͸(FOFSJDܕͰ͋Γɺ 6OJPOܕΛؚΉ
    ཁૉ ͷܕΛࢦఆͰ͖Δ
 )BTIͳͲɺଞͷίϯςφ
    ίϨΫγϣϯ
    ܕ΋ಉ༷ ܕͷ૊Έ߹ΘͤΛදݱ͢Δ6OJPOܕ a = [1, 2, 3, "we are like crystal"] #=> Array(String | Int32) a = [] of String | Int32 #=> Array(String | Int32)
14. (FOFSJDܕ ޙͰઆ໌͠·͢͠·ͤΜ
15. ϝιουݺͼग़͠ ͜Ε͸Ͳ͏ͳΔʁ
    Τϥʔʹͳͬͯ͠·͏ͷʁ ͋Δܕ
    Ϋϥε
    ʹଘࡏ͠ͳ͍ϝιουΛݺͼग़ͨ͠৔߹ a = 3 a.size
16. ϝιουݺͼग़͠ ͋Δܕ
    Ϋϥε
    ʹଘࡏ͠ͳ͍ϝιουΛݺͼग़ͨ͠৔߹ a = 3 a.size undefined method 'size' for Int32 a.size ^~~~ ͜Ε͸
    ίϯύΠϧΤϥʔ &SSPS
17. ϝιουҾ਺ def put_size(x) puts x.size end put_size("crystal") put_size(5) undefined method 'size' for Int32 puts x.size ^~~~ &SSPS Ҿ਺Ͱ౉͞ΕͨΦϒδΣΫτʹϝιου͕ͳ͍
18. ܕ੍໿ def put_size(x : String) puts x.size end put_size(5) no overload matches 'put_size' with types Int32 Overloads are: - put_size(x : String) put_size(5) ^~~~~~~~ &SSPS Ҿ਺ʹܕΞϊςʔγϣϯΛࢦఆ͠ܕΛ੍໿͢Δ
19. ܕ੍໿͕͋Δͱ҆৺ͩͶʂ
 Ҿ਺͸ͲΜͲΜܕ੍໿͠Α͏ʂ
20. 3F
    ϝιουҾ਺ def put_size(x) puts x.size end put_size("crystal") put_size([1, 2, 3]) Ҿ਺Ͱ౉͞ΕͨΦϒδΣΫτʹϝιου͕͋Δ ͑ͬʁ
21. 3F
    ϝιουҾ਺ def put_size(x) puts x.size end put_size("crystal") put_size([1, 2, 3]) Ҿ਺Ͱ౉͞ΕͨΦϒδΣΫτʹϝιου͕͋Δ 7 3 3FTVMU Τϥʔͳ͘ਖ਼ৗऴྃ͢Δ
22. 3F
    ϝιουҾ਺ def put_size(x) puts x.size end put_size("crystal") put_size([1, 2, 3]) Ҿ਺Ͱ౉͞ΕͨΦϒδΣΫτʹϝιου͕͋Δ 7 3 3FTVMU Τϥʔͳ͘ਖ਼ৗऴྃ͢Δ ໌֬ʹܕ੍໿͕͞Ε͍ͯ ͳ͚Ε͹ɺ͋Δܕ͕ݺͼ ग़͞ΕΔϝιουʹԠ౴ ͢Δͱ͖ɺίϯύΠϥͷ ܕνΣοΫ͸௨Δɻ
23. μοΫλΠϐϯάతͳܕγεςϜ ܕͦͷ΋ͷ΍ͦͷܧঝؔ܎ʹґଘ͠ͳ͍ɺ
    ॊೈੑΛ࣋ͬͨ੩తܕ෇͚ʹͳ͍ͬͯΔ γάωΠνϟ͕ಛʹॏཁͰ͋Δͱ͍͏఺Ͱɺ
 4USVDUVSBM
    4VCUZQJOH
    ߏ଄త෦෼ܕ෇͚
    ͱݴͬͯ΋Α͍͔΋
24. 3F
    3F
    ϝιουҾ਺ def put_size(x) puts x.size end put_size("crystal") put_size(5) undefined method 'size' for Int32 puts x.size ^~~~ &SSPS ܕ੍໿Λ͠ͳͯ͘΋ίϯύΠϧ࣌ʹΤϥʔ͕ัଊ͞ΕΔ ෆඞཁͳܕ੍໿͸ ॊೈੑΛܽ͘
25. Πϯελϯεม਺ Πϯελϯεม਺΋୅ೖ͞ΕΔ஋͔Βܕਪ࿦͞ΕΔ class Person getter name def initialize(@name) end end barney = Person.new "Barney" barney.name #=> "Barney" barney.name.size #=> 6
26. barney = Person.new "Barney" barney.name.size one = Person.new 1 3F
    Πϯελϯεม਺ Πϯελϯεม਺ʹҟͳΔܕΛ༩͑ͯॳظԽ ͳΜ͔͓͔͍͠ͱ͋͜Δʁ
27. barney = Person.new "Barney" barney.name.size one = Person.new 1 3F
    Πϯελϯεม਺ Πϯελϯεม਺ʹҟͳΔܕΛ༩͑ͯॳظԽ undefined method 'size' for Int32 (compile-time type is (String | Int32)) barney.name.size #=> 4 ^~~~ ͜Ε͸
    ίϯύΠϧΤϥʔ &SSPS
28. JG
    WBSJT@B ʜ JT@B
    ͰܕΛνΣοΫ੍͠ݶ͢Δ if a.is_a?(String) # ここでは a が # String で「ある」ことが保証される else # ここでは a が # String では「ない」ことが保証される end ίϯύΠϧ࣌ϦϑϨΫγϣϯʹΑΔܕͷอূ
29. JG
    WBSSFTQPOET@UP ʜ SFTQPOET@UP
    ͰԠ౴ΛνΣοΫ੍͠ݶ͢Δ if a.responds_to?(:size) # ここでは a が # size に応答「する」ことが保証される else # ここでは a が # size に応答「しない」ことが保証される end ίϯύΠϧ࣌ϦϑϨΫγϣϯʹΑΔϝιουԠ౴ͷอূ
30. 3F
    3F
    Πϯελϯεม਺ JT@B
    ΍
    SFTQPOET@UP
    Ͱ੍ݶ͢Δ if (name = barney.name).is_a?(String) name.size #=> 4 end if (name = barney.name).responds_to?(:size) name.size #=> 4 end Πϯελϯεม਺ͷ৔߹͸ɺ্هͷΑ͏ʹҰ౓ม਺ʹ୅ೖ͢Δඞཁ͕͋Δ
31. BT BT
    ͰܕΛ੍ݶ͢Δ͜ͱ΋Ͱ͖Δ name = barney.name as String name.size #=> 4 w BT͸࣮ߦ࣌ʹνΣοΫΛߦ͏
    w ର৅͕4USJOHͰͳ͔ͬͨ৔߹ʹ͸ྫ֎͕ൃੜ
    w BT͸ΩϟετͰ͸ͳ͍
    ผͷܕ΁ͷม׵͸͠ͳ͍
32. OJMBCMF ͋Δܕ͕/JMܕΛ࣋ͭՄೳੑ a = [] of String? a.class #=> Array(String?) a << "crystal" #=> ["crystal"] a << nil #=> ["crystal", nil] w 4USJOH ͸ܕ͕/JMܕΛ࣋ͭ͜ͱΛҙຯ͢Δ
    w 4USJOH
    c
    /JM
    ͱ͍͏6OJPOܕͱಉ༷
33. OJMBCMF
    Πϯελϯεม਺ JOJUJBMJ[FͰॳظԽ͞Εͳ͍Πϯελϯεม਺ class Person getter name property address def initialize(@name) end end barney = Person.new "Barney" barney.address = "Manchester" barney.address.size
34. OJMBCMF
    Πϯελϯεม਺ JOJUJBMJ[FͰॳظԽ͞Εͳ͍Πϯελϯεม਺ barney = Person.new "Barney" barney.address = "Manchester" barney.address.size undefined method 'size' for Nil (compile-time type is String?) barney.address.size ^~~~ &SSPS ͜Ε͸
    ίϯύΠϧΤϥʔ JOJUJBMJ[FͰॳظԽ͞Εͳ͍Πϯελϯεม਺͸/JMܕΛ࣋ͭ
35. 3F
    OJMBCMF
    Πϯελϯεม਺ Πϯελϯεม਺ΛJOJUJBMJ[Fͷ֎ଆͰॳظԽ͢Δ class Person getter name property address @address = "nowhere" def initialize(@name) end end barney = Person.new "Barney" barney.address = "Manchester" barney.address.size #=> 10
36. Πϯελϯεม਺ͷܕࢦఆ Πϯελϯεม਺ΛܕΞϊςʔγϣϯͰࢦఆ͢Δ class Person … @address :: String … end w !BEESFTTʹ4USJOHҎ֎ͷܕΛ୅ೖ͢ΔͱΤϥʔ
    w ܕͷσϑΥϧτ஋͸ଘࡏ͠ͳ͍ͷͰॳظԽ͸ඞཁ
37. ·ͱΊ w $SZTUBM
    㱠
    3VCZ
    w தͰ΋੩తܕ෇͚ʹΑΔҧ͍͸ඇৗʹେ͖͍ ͦΕͰ΋ɺ
    We love Ruby's efficiency for writing code. ͱ͍͏ͷ͕$SZTUBMͷग़ൃ఺ͷͭͰ͋ΔΑ͏ʹɺ
    3VCZͷॊೈੑ΍ੜ࢈ੑɺؾ͍͍࣋ͪॻ͖ຯΛҡ࣋ͯ͠
    ੩తܕ෇͚ʹ͠Α͏ͱ͢Δ޻෉͕ਵॴʹݟΒΕΔɻ
38. ࿩ͤͳ͔ͬͨ࿩୊ͨͪ w (FOFSJDܕ
    (FOFSJDT
    w ྫ֎ॲཧ಺Ͱͷܕਪ࿦ͷಇ͖
    w Ϋϩʔδϟ಺Ͱͷม਺ͷܕ
    w ϚΫϩʹ͓͚Δܕ৘ใ΁ͷΞΫηε
    w UZQFPGɺ0CKFDUUSZͳͲͷϝιου
    w FUD
    FUD
39. IUUQKBDSZTUBMMBOHPSHEPDT ࠓ೔࿩ͤͳ͔ͬͨ಺༰΋υΩϡϝϯτʹهࡌ͕͋Γ·͢
40. υΩϡϝϯτΛ͍ͭ΋VQUPEBUFʹ͢ΔͨΊʹ
    ຋༁Λख఻ͬͯ͘ΕΔํΛืू͍ͯ͠·͢ (JU)VC
    IUUQTHJUIVCDPNDSZTUBMKQKBDSZTUBMMBOHPSH (JUUFS
    IUUQTHJUUFSJNDSZTUBMKQKBDSZTUBMMBOHPSH ΋͘͠͸
    @5t111111
    ·Ͱ௚઀͓஌Β͍ͤͩ͘͞ʂ 4MBDL
    IUUQDSZTUBMQJOFNPF
41. ຊεϥΠυதͷαϯϓϧίʔυ
    ͓Αͼͦͷग़ྗ಺༰͸
    ͢΂ͯ
    $SZTUBM
    
    Ͱ֬ೝ͍ͯ͠·͢ ͝੩ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠ɻ