self in return type declaration

Transcript

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3. 3FUVSO
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   ໭Γ஋ͷܕએݴ ࢖ͬͯ·͔͢ʁ

4. function foo(): int { } ໭Γ஋ͷܕએݴͱ͸ʁ ͜Μͳ΍ͭ

5. ྫɿࣗ෼Λฦ͢ϝιου class A { public function getMe(): A { return

   $this; } }

6. ࣮͸TFMGͱॻ͚Δ class A { public function getMe(): self { return

   $this; } }

7. ΂ΜΓʂʂ

8. ҙ֎ͱ஌Βͳ͍ਓ
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11. ܧঝ͢ΔͱͲ͏ͳΔʁ class A { public function getMe(): self { return

    $this; } } class B extends A {} $b = new B(); $b->getMe(); // ?

12. ਖ਼ղ
    
    #ͷΠϯελϯε͕ฦΔ class A { public function getMe(): self { return

    $this; } } class B extends A {} $b = new B(); $b->getMe(); // instance of B

13. UIJT͸ɺ#ͷίϯςΩε τ͔Βݺ͹ΕΔͱ#ͷΠ ϯελϯεΛࢦ͢ͷͰɻ

14. ࠨͷίʔυ͸ӈͷίʔυͱ౳Ձ 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

15. ໭Γ஋ͷܕ͸ɺ
    ࣮ߦ࣌ʹSFUVSO͞Εͨࡍʹ
    JOTUBODFPG తͳ΋ͷͰ
    ͰνΣοΫ͞ΕΔ

16. ͜ͷ৔߹Ͳ͏ͳΔʁ class A { public function getMe(): self { return

    $this; } } class B extends A { public function getMe(): self { return $this; } }

17. 'BUBM
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18. ͜Ε͕μϝͳͷͱಉ͡
 γάωνϟͷෆҰக
    class A { public function getMe(): A

    … } class B extends A { public function getMe(): B … }

19. ͜͏͢Ε͹͓̺ class A { public function getMe(): self { return

    $this; } } class B extends A { public function getMe(): parent { return $this; } }

20. ͜Ε͕0,ͳͷͱಉ͡ class A { public function getMe(): A … }

    class B extends A { public function getMe(): A … }

21. ༨ஊɿ͜Ε͸কདྷͷ1)1Ͱ͸
    ՄೳʹͳΔ͔΋͠Εͳ͍ɻ ໭Γ஋ͷڞม
    class A { public function getMe():

    A } class B extends A { public function getMe(): B … } IUUQTXJLJQIQOFUSGDDPWBSJBOUSFUVSOTBOE DPOUSBWBSJBOUQBSBNFUFST

22. ͪͳΈʹܕ໊ͷͱ͜Ζʹ
    TUBUJD͸ෆՄɻ class A { public function getMe(): static …

    }

23. ·ͱΊ w ໭Γ஋ܕએݴͰTFMG
    QBSFOU ͕࢖͑Δ
    w ཚ༻͢ΔͱΘ͔Γʹ͘͘ͳΔ ͷͰదࡐదॴͰ
    w ʮJOTUBODFPGνΣοΫʯͩͱ

    ࢥ͑͹͓̺

24. ༨ஊɿϝιουͷҾ਺Ͱ΋࢖͑Δ class A { public function setMe(self $self) { $this->self

    = $self; } } class B extends A { public function setMe(parent $self) { $this->self = $self; } }

25. ͝ਗ਼ௌ͋Γ͕ͱ͏
    ͍͟͝·ͨ͠
    NN