シュッとふりかえる Ruby 2.0 以降

γϡοͱ;Γ͔͑Δ 3VCZҎ߱ ୈճ3VCZؔ੢ษڧձ ੢ଜ༑༟BLB4JYFJHIU

4JYFJHIU !UPNPIJ@SP ۙگɿ1FSM

ͬ͘͟Γͱมߋ఺Λ ;Γ͔͑Γ·͢ɻ

ͨͩ͠ɺཧղग़དྷͨͱ͜Ζ΍ɺ ڵຯͰϑΟϧλ͍ͯ͠·͢ɻ

೥݄̎೔ 3VCZੜ஀प೥

ΩʔϫʔυҾ਺ ! def meth(foo: “bar”, hoge: “piyo”) [foo, hoge] end
! p meth(foo: “cat”) #=> [“cat”, “piyo”]

3FpOFNFOUT w ޡղΛڪΕͣʹ͍͏ͱ ಛఆͷείʔϓͷதͰͷΈ ༗ޮͳϝιουΛఆٛ͢Δํ๏ w &YQFSJNFOUBMͳػೳͱͯ͠ೖΓ·ͨ͠

.PEVMFQSFQFOE module Awesome def greet "awesome " + super end
end ! class Person prepend Awesome def greet "hi!" end end ! puts Person.new.greet #=> awesome hi! w ܧঝͷઌ಄ʹૠ͠ࠐΊΔػೳ ! w JODMVEF"XFTPNF w 1FSTPO"XFTPNF w QSFQFOE"XFTPNF w "XFTPNF1FSTPO ! w 3*1BMJBT@NFUIPE@DIBJO

σϑΥϧτΤϯίʔσΟϯά ͕65'ʹͳͬͨ w FODPEJOHVUG͕ෆཁʹͳͬͨʂʂʂʂ

&OVNFSBCMFMB[Z users = [ 5ԯ݅ͷσʔλ ] p users.each.lazy. map {|u|
u.newbie? }. map {|u| u.rubyist? }. map {|u| u.age < 20 }. to_a

ͦͷଞ w J w @@EJS@@ w )BTI OJMUP@I )BTIUP@I w
DPOTU@HFU l'PP#BS#B[z w "SSBZCTFBSDI w 5SBDF1PJOU w HFNOPEPDVNFOU

೥݄೔

3(FO($ʹͳͬͨ w ύϑΥʔϚϯε޲্ʂ

ΩʔϫʔυҾ਺ͷ֦ு ! def meth(foo:, hoge:) [foo, hoge] end ! p
meth(foo: “cat”) #=> `meth': missing keywords: hoge (ArgumentError)

ϝιουఆ͕ٛ γϯϘϧΛฦ͢Α͏ʹ class A private def method # ... end
end ͭ·ΓEFGIPHFFOEIPHF

#JOEJOHMPDBM@WBSJBCMF@ HFUcTFU def span(body, class: "") html_class = binding.local_variable_get(:class) %q!<span
class="%s">%s</span>! % [html_class, body] end ! p span("hoge", class: “right”) ! #=> "<span class=\"right\">hoge</span>" ϩʔΧϧม਺Λऔಘͨ͠ΓઃఆͰ͖Δ ༧໿ޠ΋ΩʔϫʔυҾ਺ͱͯ͠࢖͑Δ

3FpOFNFOUT module Bangable refine String do def ! self +
"!" end end end ! class Person using Bangable ! def greet(name) puts "Hi #{name}".! end end ! Person.new.greet("cat") #=> Hi cat! ! puts "Hi dog".! #=> false w &YQFSJNFOUBM͕औΕͨʂ ! w ΫϥεϞδϡʔϧͷε ίʔϓʹ΋༗ޮʹ w FWBM଒ͷରԠ͸ೖΒͳ ͔ͬͨ

.PEVMFJODMVEFQSFQFOE͕ QVCMJDͳϝιουʹͳͬͨ A.include AwesomeModule A.prepend AwesomeModule A.__send__(:include, AwesomeModule) A.__send__(:prepend, AwesomeModule)

GSFF[F w શͯͷ4ZNCPM͕ϑϦʔζ͞ΕΔΑ͏ʹͳͬͨ w ϑϦʔζ͞Εͨจࣈྻ͕ಉ͡PCKFDU@JEΛฦ͢Α ͏ʹͳͬͨ w ϋογϡͷΩʔʹจࣈྻΛࢦఆ͢ΔͱϑϦʔζ͞Ε ΔΑ͏ʹͳͬͨ4ZNCPMͱಉ͡ѻ͍

ͦͷଞ w "SSBZUP@I w S J SJ w &YDFQUJPODBVTF w
,FSOFMTJOHMFUPO@NFUIPE ,FSOFMTJOHMFUPO@NFUIPE w 4USJOHTDSVC w FWBM଒͕؀ڥΛҾ͖ܧ͕ͳ͘ͳͬͨ w MBNCEB1SPD͔ΒͷSFUVSOͷڍಈͷ౷Ұ w BOENPSF

೥݄೔

\lTZNCPMLFZzlWBMVFz^ {:"symbol-key" => "value"} {“symbol-key": "value"}

($ w ΠϯΫϦϝϯλϧ($ͷಋೖ w γϯϘϧ͕($ͷର৅ʹͳͬͨ

#JOEJOH w #JOEJOHMPDBM@WBSJBCMFT w #JOEJOHSFDFJWFS class A def context x
= 1 y = 2 binding end end ! a = A.new p a.context.local_variables #=> [:x, :y] p a.context.receiver #=> #<A:0x007fa450833dc0>

.FUIPETVQFS@NFUIPE class Parent def meth end end ! class Child
< Parent def meth end end ! p Child.new.method(:meth).super_method #=> #<Method: Parent#meth> TVQFSͰݺͼग़ͤΔϝιουΛऔಘग़དྷΔΑ͏ʹͳͬͨ

.FUIPEDVSSZ def add(a, b) a + b end ! add_ten
= method(:add).curry.(10) p add_ten.(5) #=> 15 1SPDDVSSZͱಉ͜͡ͱ͕ग़དྷΔΑ͏ʹͳͬͨ

&OVNFSBCMF w TMJDF@BGUFS w TMJDF@CFGPSFͷٯ w NBY NBY@CZ NJO NJO@CZ
w Ҿ਺ΛऔΕΔΑ͏ʹͳͬͨ counts = [1, 2, 3, 4, 5] ! counts.slice_before(&:even?) #=> [[1, 2], [3, 4], [5]] ! counts.max(2) #=> 5, 4 counts.min(3) #=> 1, 2, 3

0CKFDUJUTFMG state = state.presence_in(AVAILABLE_STATES) Book.public_send(state || :itself).order(desc: :price) ࣗ෼ࣗ਎Λฦ͢ϝιου ྫ͑͹͜͏࢖͏
ࢦఆ͞Εͨεςʔτ͕༗ޮͳ΋ͷͰ͋Ε͹ͦͷத͔Βɺ ແޮͳ΋ͷͰ͋Ε͹શମ͔Βݕࡧ͢Δɻ #PPLTBMFPSEFS EFTDQSJDF ΋͘͠͸#PPLPSEFS EFTDQSJDF

$PNQBSBCMF class Person include Comparable ! attr_reader :age ! def
initialize(age) @age = age end ! def <=>(other) self.age <=> other.age end end ! a = Person.new(20) b = Person.new(18) ! p a > b #=> true ! p a == nil #=> warning: Comparable#== will no more rescue exceptions of #<=> in the next release. #=> warning: Return nil in #<=> if the comparison is inappropriate or avoid such comparison. #=> false ஫ ࣍ͷόʔδϣϯ͔Βͷྫ֎ΛӅṭͯ͘͠Εͳ͘ͳΓ·͢ɻ

ͦͷଞ w OJMUSVFGBMTF͕GSP[FOʹมߋ w 1BUIOBNF lDVUFz lDBUzlEPHz w 'JMFCJSUIUJNF w
'MPBU OFYUcQSFW @qPBU w .BUSJYpSTU@NJOPS .BUSJYDPGBDUPS w %JHFTU)."$͕ͳ͘ͳͬͨ 0QFO44-)."$ w $"1*ͷ%FQSFDBUFE͕ফ͑ͯΔ w ࡉ͔͍มߋ͕ͨ͘͞Μ͋Δ

͝ਗ਼ௌ͋Γ͕ͱ͏ ͍͟͝·ͨ͠ɻ

シュッとふりかえる Ruby 2.0 以降

シュッとふりかえる Ruby 2.0 以降

More Decks by Tomohiro Nishimura

Other Decks in Programming

Featured

Transcript