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self in return type declaration
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DQNEO
June 27, 2018
Technology
1
180
self in return type declaration
PHPの戻り値型宣言でselfを使ってみよう
DQNEO
June 27, 2018
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Transcript
!%2/&0 Ͳ͖ΎͶ͓ BU.FSDBSJ QIQTUVEZ lTFMGzJO 3FUVSO5ZQF%FDMBSBUJPO
(JUຊͷम͠·ͨ͠
3FUVSOUZQFEFDMBSBUJPO Γͷܕએݴ ͬͯ·͔͢ʁ
function foo(): int { } Γͷܕએݴͱʁ ͜Μͳͭ
ྫɿࣗΛฦ͢ϝιου class A { public function getMe(): A { return
$this; } }
࣮TFMGͱॻ͚Δ class A { public function getMe(): self { return
$this; } }
ΜΓʂʂ
ҙ֎ͱΒͳ͍ਓ ଟ͍ҹ
ެࣜυΩϡϝϯτʹ ͳ͔ͥTFMGʹ͍ͭͯ ݴٴͳ͠ IUUQQIQOFUNBOVBMFOGVODUJPOTSFUVSOJOH WBMVFTQIQGVODUJPOTSFUVSOJOHWBMVFTUZQFEFDMBSBUJPO
3'$ͷԼͷํʹখ͞ʙ͘ ॻ͍ͯ͋Δ IUUQTXJLJQIQOFUSGDSFUVSO@UZQFT
ܧঝ͢ΔͱͲ͏ͳΔʁ class A { public function getMe(): self { return
$this; } } class B extends A {} $b = new B(); $b->getMe(); // ?
ਖ਼ղ#ͷΠϯελϯε͕ฦΔ class A { public function getMe(): self { return
$this; } } class B extends A {} $b = new B(); $b->getMe(); // instance of B
UIJTɺ#ͷίϯςΩε τ͔ΒݺΕΔͱ#ͷΠ ϯελϯεΛࢦ͢ͷͰɻ
ࠨͷίʔυӈͷίʔυͱՁ class A { public function getMe(): A { return
$this; } } class B extends A {} $b = new B(); $b->getMe(); // B class A { public function getMe(): self { return $this; } } class B extends A {} $b = new B(); $b->getMe(); // B
Γͷܕɺ ࣮ߦ࣌ʹSFUVSO͞Εͨࡍʹ JOTUBODFPG తͳͷͰ ͰνΣοΫ͞ΕΔ
͜ͷ߹Ͳ͏ͳΔʁ class A { public function getMe(): self { return
$this; } } class B extends A { public function getMe(): self { return $this; } }
'BUBMFSSPS ࣮ߦ࣌ίϯύΠϧΤϥʔ 1)1'BUBMFSSPS %FDMBSBUJPOPG#HFU.F #NVTUCFDPNQBUJCMFXJUI "HFU.F "
͜Ε͕μϝͳͷͱಉ͡ γάωνϟͷෆҰக class A { public function getMe(): A
… } class B extends A { public function getMe(): B … }
͜͏͢Ε͓̺ class A { public function getMe(): self { return
$this; } } class B extends A { public function getMe(): parent { return $this; } }
͜Ε͕0,ͳͷͱಉ͡ class A { public function getMe(): A … }
class B extends A { public function getMe(): A … }
༨ஊɿ͜Εকདྷͷ1)1Ͱ ՄೳʹͳΔ͔͠Εͳ͍ɻ Γͷڞม class A { public function getMe():
A } class B extends A { public function getMe(): B … } IUUQTXJLJQIQOFUSGDDPWBSJBOUSFUVSOTBOE DPOUSBWBSJBOUQBSBNFUFST
ͪͳΈʹܕ໊ͷͱ͜Ζʹ TUBUJDෆՄɻ class A { public function getMe(): static …
}
·ͱΊ w ΓܕએݴͰTFMG QBSFOU ͕͑Δ w ཚ༻͢ΔͱΘ͔Γʹ͘͘ͳΔ ͷͰదࡐదॴͰ w ʮJOTUBODFPGνΣοΫʯͩͱ
ࢥ͓̺͑
༨ஊɿϝιουͷҾͰ͑Δ class A { public function setMe(self $self) { $this->self
= $self; } } class B extends A { public function setMe(parent $self) { $this->self = $self; } }
͝ਗ਼ௌ͋Γ͕ͱ͏ ͍͟͝·ͨ͠ NN