Ruby Under a Microscope を読んでみた （つまみぐい紹介編）

Ruby Under a Microscope 
を読んで面白かったので、一部の内容を社内勉強会「万葉究楽部」第四回で共有しました。

Transcript

1. Ruby Under a Microscope 
 ΛಡΜͰΈͨ ʢͭ·Έ͙͍঺հฤʣ ສ༿ڀָ෦ #4 2014.01.16
 ௗҪઇ @yotii23
2. جຊॻࢽ৘ใ ஶऀɿPat Shaughnessy ग़൛ࣾɿno starch press ISBNɿ9781593275273 O’REILLYɿ
 http://shop.oreilly.com/product/9781593275273.do
3. ͲΜͳ಺༰ʁ "An Illustration Guide" 
 #=> ਤೖΓͰ "to Ruby Internals"
 #=> Rubyͷ಺෦࣮૷Λղઆʂ ͍ͭ΋ॻ͍͍ͯΔRubyͷίʔυ ͕ɺͲΜͳ෩ʹ࣮ߦ͞ΕΔͷ͔ ΛɺCͷίʔυͳ͠ͰɺਤೖΓ Ͱղઆͯ͘͠ΕΔຊ Ruby 2.0ରԠ
4. 1: Tokenization and ParsingʢίʔυΛύʔπʹόϥͯ͠ɺߏจΛղੳ͢Δʣ 2: CompilationʢίϯύΠϧΑ͏͠ΒΜɺͱࢥͬͨΒKoichi Sasadaͷ໊લ͕ʣ 3: How Ruby Executes Your CodeʢRuby͸Ͳ͏΍ͬͯ͜ͷίʔυΛ࣮ߦͯ͠Δͷ͔ʣ 4: Control Structures and Method Dispatch ʢ੍ޚߏ଄ͱ͔ϝιουݺͼग़͠ͱ͔ʣ 5: Objects and ClassesʢΦϒδΣΫτͱΫϥεɺͳɻ͋Εͳɻʣ 6: Method Lookup and Constant Lookup ʢϝιου୳ࡧͱఆ਺୳ࡧʣ 7: The Hash Table: The Workhorse of Ruby Internals
 ʢϋογϡςʔϒϧɺRuby಺෦ͷ͸ͨΒ͖Ϟϊʣ 8: How Ruby Borrowed a Decades-Old Idea from Lisp
 ʢϒϩοΫ͸Rubyಠࣗͷಛ௃ͱ͔͡ΌͶ͔͑Βʂʣ 9: Metaprogramming ʢࠇຐज़ʣ 10: JRuby: Ruby on the JVM ʢJVMʣ, 11: Rubinius: Ruby Implemented with Ruby ʢRubiniusʣ 12: Garbage Collection in MRI, JRuby, and Rubinius ʢॲཧܥʹΑΔGC͍Ζ͍Ζʣ ໨࣍ͬ͟ͱݟ
5. ΦϒδΣΫτͱΫϥε
 ɾΦϒδΣΫτͷ಺෦ߏ଄
 ɾΠϯελϯεม਺ͷ୳ࡧํ๏
 ɾΫϥεͷ಺෦ߏ଄ Ϟδϡʔϧ: include, extend, prepend ຊ೔ͷͭ·Έ͙͍ϝχϡʔ
6. ΦϒδΣΫτͱΫϥε
7. ΦϒδΣΫτͷ಺෦ߏ଄ จதఆٛ: “͢΂ͯͷRubyͷΦϒ δΣΫτ͸ɺΫϥε ϙΠϯλͱΠϯελ ϯεม਺ͷ഑ྻͷί ϯϏͰ͋Δ” ko1νΣοΫ:ϢʔβʔఆٛΫϥεͷ͜ͱɻ
 Πϯελϯεม਺഑ྻͷͳ͍ΦϒδΣΫτ΋͋Δ
8. ΦϒδΣΫτͷ಺෦ߏ଄ RObject :ΦϒδΣΫτߏ଄ମ RBasic: ΦϒδΣΫτͷجຊཁૉ flags:಺෦తͳ͍ΖΜͳਅِ஋ͳͲ klass:classΛࣔ͢ϙΠϯλ numiv:Πϯελϯεม਺ͷ਺ ivptr:Πϯελϯεม਺ͷ഑ྻΛ ࣔ͢ϙΠϯλ
9. ྫʣಉ͡Ϋϥεͷ̎ͭͷΦϒδΣΫτ class Mathematician attr_accesor :first_name attr_accesor :last_name end ! euler = Mathematician.new euler.first_name = “Leonhard” euler.last_name = “Euler” ! euclid = Mathematician.new euclid.first_name = “Euclid” RClass Mathematician RObject klass numiv: 2 ivptr RObject klass numiv: 1 ivptr Leonhard Euler Euclid
10. δΣωϦοΫΦϒδΣΫτ
 simple ruby value String info… Array info… VALUE RSring flags klass RBasic VALUE RArray flags klass RBasic integer value Flags RObject δΣωϦοΫΦϒδΣΫτ FIXNUM_FLAG : 1 simple ruby value RObject numiv ivptr VALUE flags klass RBasic ଞɺRRegexp ͳͲ૊ΈࠐΈͷ
 ΦϒδΣΫτ ଞɺsymbolͳͲ ୯७ͳ஋
11. δΣωϦοΫΦϒδΣΫτͷ
 Πϯελϯεม਺ > str = “ͳʹ͔จࣈྻ => “ͳʹ͔จࣈྻ” > str.instance_variables => [ ] > str.instance_variables_set(“@val1”, “value one”) => “value one” > str.instance_variables => [:@val1] RSring generic_iv_tbl “ͳʹ͔จࣈྻ” str => hash etc… etc… @val1 => “value 1” @val2 => “value 2”
12. Πϯελϯεม਺ͷ୳͠ํ _ko1ઌੜߨٛϊʔτ value Flags valueͷflags ʹΑͬͯ
 ߏ଄ମΛ͔࣋ͭ൑ผ RObject δΣωϦοΫΦϒδΣΫτ simple ruby value ࣋ͨͳ͍ RBasicͷflagsͰ δΣωϦοΫΦϒδΣΫτ͔൑ผ ࣋ͭ flags klass RBasic ࣗ෼ͷ஋Λkeyʹɺgeneric_iv_tblΛ୳͢ ࣗ෼ͷclassͱivptr͔Β
 ୳͢
13. genelic_iv_table͸஗͍ _ko1ઌੜߨٛϊʔτ Object String Regexp
14. ivptr (instance variables pointer) Ruby1.8 Ruby1.9 RObject klass numiv: 2 ivptr @val1 => “value 1” @val2 => “value 2” RClass RObject klass numiv: 2 ivptr ”value 1” “value 2” @val1 => 0 @val2 => 1
15. ɹΈ͖ͯͨ͜ͱɿΦϒδΣΫτ ΦϒδΣΫτͷ಺෦ߏ଄
 ɾΫϥεϙΠϯλ
 ɾ͍͔ͭ͘ͷΦϒδΣΫτͷछྨͱߏ੒
 ɾΦϒδΣΫτม਺ͷΞΫηε
16. Ϋϥεͷߏ଄ จதఆٛɿ ”Ϋϥε͸ϝιουఆٛɺ attribute namesɺεʔύʔ Ϋϥε΁ͷϙΠϯλɺఆ ਺ςʔϒϧΛ࣋ͬͨRuby ͷΦϒδΣΫτͰ͋Δ” http://www.flickr.com/photos/22326055@N06/5220652648/sizes/m/
17. Πϯελϯεϝιουͱ
 Πϯελϯεม਺໊ DMBTT
    .BUIFNBUJDJBO
    
    
    EFG
    pSTU@OBNF
    
    
    
    
    
    !pSTU@OBNF
    
    
    FOE
    
    
    EFG
    pSTU@OBNF WBM
    
    
    
    
    !pSTU@OBNF
    
    WBM
    
    
    FOE
    
    
    EFG
    MBTU@OBNF
    
    
    
    
    !MBTU@OBNF
    
    
    FOE
    
    
    EFG
    MBTU@OBNF WBM
    
    
    
    
    !MBTU@OBNF
    
    WBM
    
    
    FOE
    FOE RClass flags klass RBasic method table first_name first_name= last_name last_name= attribute names @first_name @last_name Ruby͸Ϋϥε΋ΦϒδΣΫτʂ
18. Ϋϥεͷܧঝ DMBTT
    .BUIFNBUJDJBO
    
    1FSTPO
    
    ҎԼུʣ 
    Q
    .BUIFNBUJDJBODMBTT
    
    
    
    
    $MBTT 
    Q
    .BUIFNBUJDJBOTVQFSDMBTT
    
    
    
    
    1FSTPO RClass RClass flags klass RBasic method table first_name first_name= last_name last_name= attribute names @first_name @last_name Class RClass Person super superclass:
19. ΫϥεͷΠϯελϯεม਺ͱ Ϋϥεม਺ DMBTT
    .BUIFNBUJDJBO
    
    
    !UZQF
    
    l(FOFSBMz
    
    
    EFG
    TFMGUZQF
    
    
    
    
    
    !UZQF
    
    
    FOE
    FOE
    ! $MBTT
    4UBUJTUJDJBO
    
    .BUIFNBUJDJBO
    
    
    
    !UZQF
    
    l4UBUJTUJDTz
    FOE
    ! QVUT
    4UBUJTUJDJBOUZQF
    
    
    
    
    ໰୊
    QVUT
    .BUIFNBUJDJBOUZQF
    
    
    
    
    ໰୊ DMBTT
    .BUIFNBUJDJBO
    
    
    !!UZQF
    
    l(FOFSBMz
    
    
    EFG
    TFMGUZQF
    
    
    
    
    
    !!UZQF
    
    
    FOE
    FOE
    ! $MBTT
    4UBUJTUJDJBO
    
    .BUIFNBUJDJBO
    
    
    
    !!UZQF
    
    l4UBUJTUJDTz
    FOE
    ! QVUT
    4UBUJTUJDJBOUZQF
    
    
    
    
    ໰୊
    QVUT
    .BUIFNBUJDJBOUZQF
    
    
    
    
    ໰୊
20. ΫϥεͷΠϯελϯεม਺ͱ Ϋϥεม਺ DMBTT
    .BUIFNBUJDJBO
    
    
    !UZQF
    
    l(FOFSBMz
    
    
    EFG
    TFMGUZQF
    
    
    
    
    
    !UZQF
    
    
    FOE
    FOE
    ! $MBTT
    4UBUJTUJDJBO
    
    .BUIFNBUJDJBO
    
    
    
    !UZQF
    
    l4UBUJTUJDTz
    FOE
    ! QVUT
    4UBUJTUJDJBOUZQF
    
    
    
    
    l4UBUJTUJDTz
    QVUT
    .BUIFNBUJDJBOUZQF
    
    
    
    
    l(FOFSBMz DMBTT
    .BUIFNBUJDJBO
    
    
    !!UZQF
    
    l(FOFSBMz
    
    
    EFG
    TFMGUZQF
    
    
    
    
    
    !!UZQF
    
    
    FOE
    FOE
    ! $MBTT
    4UBUJTUJDJBO
    
    .BUIFNBUJDJBO
    
    
    
    !!UZQF
    
    l4UBUJTUJDTz
    FOE
    ! QVUT
    4UBUJTUJDJBOUZQF
    
    
    
    
    l4UBUJTUJDTz
    QVUT
    .BUIFNBUJDJBOUZQF
    
    
    
    
    l4UBUJTUJDTz
21. ΫϥεͷΠϯελϯεม਺ͱ Ϋϥεม਺ RClass ΫϥεϨϕϧ
 Πϯελϯεม਺: ˏtype @@type ͲͪΒ΋֨ೲ͞ΕΔςʔϒ ϧ͸Ұॹ ҧ͏ͷ͸ΞΫηεͷ࢓ํ
22. ΫϥεͷΠϯελϯεม਺ͱ Ϋϥεม਺ RClass: Mathematician ΫϥεϨϕϧΠϯελϯεม਺: “General” etc… DMBTT
    .BUIFNBUJDJBO
    
    
    !UZQF
    
    l(FOFSBMz
    FOE DMBTT
    4UBUJTUJDJBO
    
    
    !UZQF
    
    l4UBUJTUJDTz
    FOE RClass: Statistician ΫϥεϨϕϧΠϯελϯεม਺: “Statistics” etc… ΫϥεͷΠϯελϯεม਺ @type
23. ΫϥεͷΠϯελϯεม਺ͱ Ϋϥεม਺ RClass: Mathematician ΫϥεϨϕϧΠϯελϯεม਺: “General” etc… DMBTT
    4UBUJTUJDJBO
    
    
    !!UZQF
    
    l4UBUJTUJDTz
    FOE RClass: Statistician Ϋϥεม਺ @@type @@type͋Δʁ @@type͋Δʁ super ΫϥεϨϕϧΠϯελϯεม਺:
24. ΫϥεͷΠϯελϯεม਺ͱ Ϋϥεม਺ DMBTT
    4UBUJTUJDJBO
    
    
    !!UZQF
    
    l4UBUJTUJDTz
    FOE ΫϥεͷΠϯελϯεม਺ @@type @@typeͳ͍… @@type͋Δ! ॻ͖׵͑Δʂ RClass: Mathematician ΫϥεϨϕϧΠϯελϯεม਺: “Statistic” etc… RClass: Statistician super ΫϥεϨϕϧΠϯελϯεม਺:
25. ࣮ࡍͷΫϥεͷ಺෦ߏ଄ VALUE rb_classext_struct RClass RBasic flags klass m_tbl iv_index_tbl ptr super iv_tbl const_tbl origin refined_class allocator ΫϥεϙΠϯλ ϝιουςʔϒϧϙΠϯλ Πϯελϯεม਺໊ςʔϒϧ εʔύʔΫϥεϙΠϯλ ΫϥεϨϕϧΠϯελϯεม਺ɾΫϥεม਺ ఆ਺ςʔϒϧ ৽͍͠ΦϒδΣΫτͷϝϞϦ֬อʹ࢖͏ Module#prependʹ࢖͏ refinementsʹ࢖͏
26. Ϋϥεϝιου Ϋϥεϝιου͸Ͳ͜ʹఆ ٛ͞ΕΔʁ DMBTT
    .BUIFNBUJDJBO
    
    
    DMBTT
    
    TFMG
    
    
    
    
    EFG
    DMBTT@NFUIPE
    
    
    
    
    
    
    QVUT
    lDMBTT
    NFUIPEz
    
    
    
    
    FOE
    
    
    FOE
    FOE
27. Ϋϥεϝιου RClass: Mathematician klass RClass: Class m_tbl “class_method” ? 
    DMBTT
    "OPUIFS$MBTT
    FOE
    
    "OPUIFS$MBTTDMBTT@NFUIPE
    
    VOEFpOFE
    NFUIPE
    lDMBTT@NFUIPEzʜ MathematicianΫϥε͸Class ΫϥεͷΦϒδΣΫτ
 =>Ϋϥεϝιου͸Class Ϋϥεʹఆٛ͞ΕΔ
 #=> false!
28. Ϋϥεϝιου:Ϋϥεͷੜ੒ 
    0CKFDU4QBDFDPVOU@PCKFDUT<5@$-"44>
    
    
    
    
    
    DMBTT
    .BUIFNBUJDJBO
    FOE
    
    
    
    OJM
    
    0CKFDU4QBDFDPVOU@PCKFDUT<5@$-"44>
    
    
    
    
    ໰୊
    ObjectSpace.count_objects[:T_CLASS] … Ϋϥεͷ਺ΛΧ΢ϯτ͢Δ ໰୊ɿҰͭΫϥεΛ৽͘͠ੜ੒ͨ࣌͠ɺ
 Ϋϥεͷ૯਺͸͍ͭ͘૿͑Δ͔
29. Ϋϥεϝιου:Ϋϥεͷੜ੒ 
    0CKFDU4QBDFDPVOU@PCKFDUT<5@$-"44>
    
    
    
    
    
    DMBTT
    .BUIFNBUJDJBO
    FOE
    
    
    
    OJM
    
    0CKFDU4QBDFDPVOU@PCKFDUT<5@$-"44>
    
    
    
    
    ౴͑ɿ+ 2 ObjectSpace.count_objects[:T_CLASS] … Ϋϥεͷ਺ΛΧ΢ϯτ͢Δ
30. Ϋϥεϝιου:Ϋϥεͷੜ੒ RObject klass RClass: Mathematician RClass method tablel first_name= first_name last_name= last_name flags klass RBasic flags klass RBasic method table class_method Singleton_class <Class: Mathematician> RClass: Class m_tbl m_tbl
31. Έ͖ͯͨ͜ͱ2ɿΫϥε Ϋϥεͷ಺෦ߏ଄
 ɾΠϯελϯεม਺ͱΠϯελϯεϝιου
 ɾܧঝͷsuper
 ɾΫϥεͷΠϯελϯεม਺ʗΫϥεม਺ ΫϥεϝιουͱγϯάϧτϯΫϥε
32. Ϟδϡʔϧ http://www.flickr.com/photos/glitchpunk/5320924205/sizes/m
33. Ϟδϡʔϧͷ಺෦ߏ଄ m_tbl VALUE RClass:module rb_classext_struct RBasic flags klass ptr super iv_tbl const_tbl origin ModuleͰ͔ͭΘͳ͍΋ͷ ɾiv_index_tbl: Πϯελϯεม਺໊ςʔϒϧɹɹ ɾallocator: ৽͍͠ΦϒδΣΫτͷϝϞϦ֬ อ༻ 
 ※Ϟδϡʔϧ͸ΠϯελϯεΛ࡞Εͳ͍ ※಺෦తʹ͸super͸࣋ͭ
 ʢ೚ҙͷsuperΛࢦఆ͢Δ͜ͱ͸ग़དྷͳ͍ʣ
34. Ϋϥεܧঝؔ܎ͷϝιου୳ࡧॱ RClass: Mathematician super RClass: Person super DMBTT
    .BUIFNBUJDJBO
    
    1FSTPO
    FOE RClass: AnotherSClass super RClass: Object super 1 3 2 4
35. Ϟδϡʔϧͷϝιου୳ࡧॱ RClass: Mathematician super RClass: Person super RClass: Object NPEVMF
    1SPGFTTPS
    FOE
    ! DMBTT
    .BUIFNBUJDJBO
    
    1FSTPO
    
    
    
    JODMVEF
    1SPGFTTPS
    FOE
    RClass: AnotherSClass RClass: Professor super super 1 3 2 4 5
36. Ϟδϡʔϧ…includeͷ࣮૷ RClass: Mathematician super RClass: Person super RClass: Professor RClass: AnotherSClass super RClass: Object super 1 3 2 4 5 RClass: Professor super inculde࣌ʹϞδϡʔϧͷίϐʔ͕ Ϋϥεͱͯ͠࡞੒͞Εɺ ܧঝπϦʔʹࠩ͠ࠐ·ΕΔ super ίϐʔʂ (module) (class)
37. 1ͭͷΫϥεʹೋͭͷϞδϡʔϧ DMBTT
    .BUIFNBUJDJBO
    
    1FSTPO
    
    
    
    JODMVEF
    1SPGFTTPS
    
    
    
    JODMVEF
    &NQMPZFF
    FOE
    RClass: Mathematician super RClass: Person super RClass: Professor 1 4 2 RClass: Professor ίϐʔʂ super RClass: Employee RClass: Employee super 3
38. ϞδϡʔϧΛΠϯΫϧʔυͨ͠
 Ϟδϡʔϧ NPEVMF
    1SPGFTTPS
    
    
    
    JODMVEF
    &NQMPZFF
    FOE RClass: Professor super RClass: Employee super RClass: Employee super ίϐʔʂ Ϟδϡʔϧͷsuper͕includeͨ͠
 ϞδϡʔϧͷίϐʔΫϥεΛࢦ͢
39. ϞδϡʔϧΛΠϯΫϧʔυͨ͠
 ϞδϡʔϧͷΠϯΫϧʔυ NPEVMF
    1SPGFTTPS
    
    
    
    JODMVEF
    &NQMPZFF
    FOE
    DMBTT
    .BUIFNBUJDJBO
    
    1FSTPO
    
    
    
    JODMVEF
    1SPGFTTPS
    FOE RClass: Mathematician super RClass: Person super 1 4 2 ίϐʔʂ RClass: Professor super RClass: Employee super RClass: Professor super RClass: Employee super RClass: Employee super 3
40. Ϟδϡʔϧ…extendͷ࣮૷ RObject: klass RClass: Person super 1 3 2 extend࣌ʹϞδϡʔϧͷίϐʔΫϥε͕
 ࡞੒͞ΕɺΦϒδΣΫτͷΫϥεʹͳΔ RClass: Professor RClass: Professor super super ίϐʔʂ (module) (class) RClass: Mathematician super NPEVMF
    1SPGFTTPS
    FOE
    DMBTT
    .BUIFNBUJDJBO
    
    1FSTPO
    FOE
    N
    
    .BUIFNBUJDJBOOFX
    NFYUFOE
    1SPGFTTPS
41. Ϟδϡʔϧ…prepend (1. includeͰ͏·͘ߦ͔ͳ͍ྫ) NPEVMF
    1SPGFTPS
    
    
    
    
    EFG
    OBNF
    
    
    
    
    
    
    
    
    l1SPG
    \TVQFS^z
    
    
    
    
    FOE
    FOE
    ! DMBTT
    .BUIFNBUJDJBO
    
    
    
    BUUS@BDDFTTPS
    OBNF
    
    
    
    JODMVEF
    1SPGFTTPS
    FOE
    ! QPJODBSF
    
    .BUIFNBUJDBOOFX
    QPJODBSFOBNF
    
    l)FOSJ
    1PJODBSFz
    ! Q
    QPJODBSFOBNF
    
    
    
    
    
    l)FOSJ
    1PJODBSFz ˌinclude ”Prof.”͕͔ͭͳ͍ RClass: Mathematician super RClass: Object super RClass: Professor super 1 2 3 attr_accessor: name def name “Prof. #{name}” end Mathematican͕ઌʹ୳͞ΕΔ
 …Professor ·Ͱ୳͞ͳ͍Ͱղܾ
42. Ϟδϡʔϧ…prepend ʢ̎.prependͰղܾͨ͠ྫʣ NPEVMF
    1SPGFTPS
    
    
    
    
    EFG
    OBNF
    
    
    
    
    
    
    
    
    l1SPG
    \TVQFS^z
    
    
    
    
    FOE
    FOE
    ! DMBTT
    .BUIFNBUJDJBO
    
    
    
    BUUS@BDDFTTPS
    OBNF
    
    
    
    QSFQFOE
    1SPGFTTPS
    FOE
    ! QPJODBSF
    
    .BUIFNBUJDBOOFX
    QPJODBSFOBNF
    
    l)FOSJ
    1PJODBSFz
    ! Q
    QPJODBSFOBNF
    
    
    
    
    
    l1SPG
    )FOSJ
    1PJODBSFz ˌprepend RClass: Mathematician super RClass: Object super RClass: Professor super 1 2 3 attr_accessor :name def name “Prof. #{name}” end Professor͕ઌʹ୳͞ΕΔ ٙ໰ɿpoincare͸MathematicianͷΦϒδΣΫτ
 Ͳ͏΍ͬͯܧঝπϦʔΛલʹ໭Δͷʁ
43. Ϟδϡʔϧ…prependͷ࣮૷ RClass: Mathematician super RClass: Oject super RClass: Professor super attr_accessor :name def name “Prof. #{name}” end RClass: Mathematician super origin #prepend͸
 1. Mathematican
 ͷίϐʔ(OriginΫϥεʣΛɺ
 ΠϯΫϧʔυ͞ΕͨϞδϡʔϧͷ
 εʔύʔΫϥεʹ͢Δɻ 2. ΦϦδφϧͷΫϥεͷ
 શͯͷϝιουΛɺ
 OriginΫϥεʹҠ͢ Original Origin
44. ໰୊: ΠϯΫϧʔυޙͷϞδϡʔϧ΁ͷ
 ϝιου௥Ճ NPEVMF
    1SPGFTPS
    FOE
    ! DMBTT
    .BUIFNBUJDJBO
    
    
    
    JODMVEF
    1SPGFTTPS
    FOE
    ! NPEVMF
    1SPGFTTPS
    
    
    
    EFG
    QSJNBSZ@DMBTTSPPN
    
    
    
    
    
    
    
    Q
    l"z
    
    
    
    FOE
    FOE
    ! QPJODBSF
    
    .BUIFNBUJDJBOOFX
    ! QPJODBSFQSJNBSZ@DMBTTSPPN
    
    
    
    
    
    ໰୊ ΠϯΫϧʔυޙʹϞδϡʔϧΛ
 ࠶Φʔϓϯͯ͠ϝιουΛ௥Ճ No Method Error? or “A-101”?
45. ղ౴: ΠϯΫϧʔυޙͷϞδϡʔϧ΁ͷ
 ϝιου௥Ճ QPJODBSFQSJNBSZ@DMBTTSPPN
    
    
    
    
    
    l"z ΠϯΫϧʔυޙʹϞδϡʔϧʹ௥Ճ͞Εͨ
 ϝιου΋ݺͼग़ͤΔ
 ˎϝιουςʔϒϧͰ͸ͳ͘ɺ
 ϝιουςʔϒϧ΁ͷϙΠϯλΛίϐʔ͢ΔͨΊ method table primary_classroom RClass: Mathematician super ίϐʔʂ RClass: Professor super m_tbl RClass: Professor super m_tbl
46. Έ͖ͯͨ͜ͱ3ɿ Ϟδϡʔϧ Ϟδϡʔϧͷ಺෦ߏ଄ include/extend/prepend ͷ࣮૷
47. ·ͱΊ Ruby Under a Microscope : 
 Rubyͷϝδϟʔͳͱ͜Ζͷ಺෦ߏ଄Λେ·͔ʹཧղ ͤͯ͘͞ΕΔྑ͍ຊ ʮ͜͏͍͏͜ͱΛ͢Δͱ͜ͷڍಈʹͳΔʯͷཧ༝͕ ෼͔ΔͱRubyͱ஥ྑ͘ͳΕΔؾ͕͢Δ ͝঺հͨ͠ͷ͸΄ΜͷҰ෦Ͱ͢