Kotlin 1.3 さらっとContracts + α

LINE Developers Meetup #47 in Fukuoka

Transcript

1. Kotlin 1.3
   ͞ΒͬͱContracts + α
   LINE Developers Meetup #47 in Fukuoka
   @dashimaki_dofu
   

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2. ϓϩϑΟʔϧ
   • ໊લ: ߴ Յହ (Yoshiyasu KO)
   • ॴଐ: ϕΨίʔϙϨʔγϣϯ
   • AndroidΤϯδχΞ
   • : @dashimaki_dofu
   

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3. ϓϩϑΟʔϧ
   ʮ͠ΜͪΌΜͷਓʯͱ֮͑ͯؼ͍ͬͯͩ͘͞
   • ໊લ: ߴ Յହ (Yoshiyasu KO)
   • ॴଐ: ϕΨίʔϙϨʔγϣϯ
   • AndroidΤϯδχΞ
   • : @dashimaki_dofu
   

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4. What is Kotlin?
   

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5. Kotlinʢ͜ͱΓΜʣ
   • 2013೥ JetBrains͕ࣾ։ൃͨ͠
   ΦϒδΣΫτࢦ޲ܕݴޠ
   • JVM্Ͱಈ࡞
   • Android Studio 3.0ΑΓ
   ެࣜαϙʔτ
   

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6. 2018.10.30
   Kotlin 1.3ϦϦʔεʂ
   

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7. Kotlin 1.3
   • Coroutines ਖ਼ࣜ൛
   • Kotlin/Native β൛
   • Contracts
   • when Ҿ਺ͷείʔϓ࠷దԽ etc...
   

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8. Kotlin 1.3
   • Coroutines ਖ਼ࣜ൛
   • Kotlin/Native β൛
   • Contracts
   • when Ҿ਺ͷείʔϓ࠷దԽ etc...
   ࠓ೔࿩͢ͷ͸ͪ͜Β
   

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9. Contracts
   

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10. Contracts = ܖ໿
    • ؔ਺ͷৼΔ෣͍Λʮܖ໿ʯ͢Δ
    • ίϯύΠϥʹؔ਺ͷৼΔ෣͍Λڭ͑Δ
    

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11. ?????
    

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12. Smart Cast
    fun foo(s: String?) {
    if (s != null) s.length
    }
    

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13. Smart Cast
    fun foo(s: String?) {
    if (s != null) s.length
    } T͸/VMMBCMF
    

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14. Smart Cast
    fun foo(s: String?) {
    if (s != null) s.length
    }
    /PU/VMMΛอূ
    

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15. Smart Cast
    fun foo(s: String?) {
    if (s != null) s.length
    }
    /PU/VMMΛอূ ͕ෆཁ
    

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16. ྫ: isNullOrEmpty()
    fun foo(s: String?) {
    if (!s.isNullOrEmpty()) s!!.length
    }
    ~ Kotlin 1.2
    

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17. ྫ: isNullOrEmpty()
    fun foo(s: String?) {
    if (!s.isNullOrEmpty()) s!!.length
    }
    T͕ʮOVMMPSۭจࣈʯͰ͋Ε͹USVF
    OVMMͰ΋ۭจࣈͰ΋ͳ͚Ε͹GBMTF
    GBMTFͰ͋Ε͹/PU/VMM͕อূ͞ΕΔ͸ͣ
    ~ Kotlin 1.2
    

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18. ྫ: isNullOrEmpty()
    fun foo(s: String?) {
    if (!s.isNullOrEmpty()) s!!.length
    }
    ίϯύΠϥ͸JT/VMM0S&NQUZͷʮৼΔ෣͍ʯ͕෼͔Βͳ͍
    4NBSU$BTU͕ޮ͔ͳ͍ɾɾɾ
    ~ Kotlin 1.2
    

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19. ྫ: isNullOrEmpty()
    fun foo(s: String?) {
    if (!s.isNullOrEmpty()) s.length
    }
    Kotlin 1.3
    JT/VMM0S&NQUZʹ࣮૷͞Εͨ$POUSBDUTʹΑͬͯ
    4NBSU$BTU͕ޮ͘Α͏ʹͳΔʂ
    

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20. ྫ: isNullOrEmpty()
    @kotlin.internal.InlineOnly
    public inline fun CharSequence?.isNullOrEmpty(): Boolean {
    contract {
    returns(false) implies (this@isNullOrEmpty != null)
    }
    return this == null || this.length == 0
    }
    Kotlin 1.3
    

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21. ྫ: isNullOrEmpty()
    @kotlin.internal.InlineOnly
    public inline fun CharSequence?.isNullOrEmpty(): Boolean {
    contract {
    returns(false) implies (this@isNullOrEmpty != null)
    }
    return this == null || this.length == 0
    }
    Kotlin 1.3
    

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22. ྫ: isNullOrEmpty()
    @kotlin.internal.InlineOnly
    public inline fun CharSequence?.isNullOrEmpty(): Boolean {
    contract {
    returns(false) implies (this@isNullOrEmpty != null)
    }
    return this == null || this.length == 0
    }
    %4- ޙड़
    Ͱهड़͞ΕΔ
    Kotlin 1.3
    

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23. ྫ: isNullOrEmpty()
    @kotlin.internal.InlineOnly
    public inline fun CharSequence?.isNullOrEmpty(): Boolean {
    contract {
    returns(false) implies (this@isNullOrEmpty != null)
    }
    return this == null || this.length == 0
    }
    GBMTFΛฦ࣌͢
    Kotlin 1.3
    

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24. ྫ: isNullOrEmpty()
    @kotlin.internal.InlineOnly
    public inline fun CharSequence?.isNullOrEmpty(): Boolean {
    contract {
    returns(false) implies (this@isNullOrEmpty != null)
    }
    return this == null || this.length == 0
    }
    GBMTFΛฦ࣌͢ /PU/VMMΛอূ͢Δ͜ͱΛ
    ܖ໿͢Δ
    Kotlin 1.3
    

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25. ྫ: isNullOrEmpty()
    @kotlin.internal.InlineOnly
    public inline fun CharSequence?.isNullOrEmpty(): Boolean {
    contract {
    returns(false) implies (this@isNullOrEmpty != null)
    }
    return this == null || this.length == 0
    }
    GBMTFΛฦ࣌͢ /PU/VMMΛอূ͢Δ͜ͱΛ
    ܖ໿͢Δ
    ίϯύΠϥʹؔ਺ͷৼΔ෣͍Λ఻͑Δ͜ͱ͕Ͱ͖Δ
    Kotlin 1.3
    

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26. Contracts DSL
    • returns()
    • ؔ਺ͷ࣮ߦʹ੒ޭͨ࣌͠
    • returns(Boolean?)
    • ؔ਺͕Ҿ਺ͷ஋Λฦͨ࣌͠
    • returnsNotNull()
    • ؔ਺͕NotNullΛฦͨ࣌͠
    • callsInPrace(block, InvocationKind)
    • block ͕ݺ͹ΕΔճ਺Λ InvocationKind Ͱอূ͢Δ
    

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27. Contracts DSL
    • returns()
    • ؔ਺ͷ࣮ߦʹ੒ޭͨ࣌͠
    • returns(Boolean?)
    • ؔ਺͕Ҿ਺ͷ஋Λฦͨ࣌͠
    • returnsNotNull()
    • ؔ਺͕NotNullΛฦͨ࣌͠
    • callsInPrace(block, InvocationKind)
    • block ͕ݺ͹ΕΔճ਺Λ InvocationKind Ͱอূ͢Δ
    ࣗ෼Ͱ$POUSBDUΛ࡞ΕΔ
    $VTUPN$POUSBDUT
    

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28. when Ҿ਺ͷείʔϓ࠷దԽ
    

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29. when Ҿ਺ͷείʔϓ࠷దԽ
    fun Request.getBody() {
    val response = executeRequest()
    return when (response) {
    is Success -> response.body
    is HttpError -> throw HttpException(response.status)
    }
    }
    ~ Kotlin 1.2
    

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30. when Ҿ਺ͷείʔϓ࠷దԽ
    fun Request.getBody() {
    val response = executeRequest()
    return when (response) {
    is Success -> response.body
    is HttpError -> throw HttpException(response.status)
    }
    }
    ~ Kotlin 1.2
    ϩʔΧϧม਺Λ͜͜Ͱ
    ఆٛ͢Δඞཁ͕͋Δ
    

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31. when Ҿ਺ͷείʔϓ࠷దԽ
    fun Request.getBody() {
    val response = executeRequest()
    return when (response) {
    is Success -> response.body
    is HttpError -> throw HttpException(response.status)
    }
    }
    ~ Kotlin 1.2
    ϩʔΧϧม਺Λ͜͜Ͱ
    ఆٛ͢Δඞཁ͕͋Δ
    XIFO͚ͩͰ࢖͏ม਺ͷείʔϓ͕޿͕ͬͯ͠·͏
    

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32. when Ҿ਺ͷείʔϓ࠷దԽ
    fun Request.getBody() =
    when (val response = executeRequest()) {
    is Success -> response.body
    is HttpError -> throw HttpException(response.status)
    }
    Kotlin 1.3
    

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33. when Ҿ਺ͷείʔϓ࠷దԽ
    fun Request.getBody() =
    when (val response = executeRequest()) {
    is Success -> response.body
    is HttpError -> throw HttpException(response.status)
    }
    Kotlin 1.3
    Ҿ਺಺ͰϩʔΧϧม਺͕
    ఆٛͰ͖Δ
    

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34. when Ҿ਺ͷείʔϓ࠷దԽ
    fun Request.getBody() =
    when (val response = executeRequest()) {
    is Success -> response.body
    is HttpError -> throw HttpException(response.status)
    }
    Kotlin 1.3
    Ҿ਺಺ͰϩʔΧϧม਺͕
    ఆٛͰ͖Δ
    Ҿ਺Ͱར༻͢Δม਺ͷείʔϓΛ
    XIFOϒϩοΫ಺ͰऩΊΔ͜ͱ͕Ͱ͖Δ
    \
    

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35. ࠓ೔࿩ͨ͜͠ͱ
    • Contract
    • ίϯύΠϥʹؔ਺ͷʮৼΔ෣͍ʯΛ఻͑Δ
    • ελϯμʔυϥΠϒϥϦʹ΋૊Έࠐ·Ε͍ͯΔ
    • DSL Ͱهड़͞ΕΔ
    • Custom Contracts ΋ఆٛͰ͖Δ
    • when จͷҾ਺ͷείʔϓ࠷దԽ
    • ϩʔΧϧม਺ΛҾ਺಺ͰఆٛͰ͖Δ
    • when ϒϩοΫ಺ʹείʔϓ͕ऩΊΒΕΔ
    

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36. ·ͱΊ
    

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37. ͔Ώ͍ॴʹ
    ख͕ಧ͍ͨκʂ
    

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38. ͡Ό
    ͦΏ͜ͱͰʙ
    

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