RecordDotSyntaxのあれこれ

Transcript

1. Record Dot Syntax ͷ͋Ε͜Ε By lotz
 2019/12/11 ୈ2ճGHCษڧձ @ IIJ-II

2. RecordDotSyntax https://github.com/shayne-fletcher-da/ghc-proposals/blob/record-dot-syntax/proposals/0000-record-dot-syntax.md#motivation

3. RecordDotSyntaxͷجຊ https://github.com/shayne-fletcher-da/ghc-proposals/blob/record-dot-syntax/proposals/0000-record-dot-syntax.md#recorddotsyntax-language-extension

4. RecordDotSyntaxͷ೿ੜߏจ https://github.com/shayne-fletcher-da/ghc-proposals/blob/record-dot-syntax/proposals/0000-record-dot-syntax.md#recorddotsyntax-language-extension

5. Recordվળͷ্ʹ͋Δ ()$֦ு1SPQPTBM ()$
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6. DAMLͰͷ࣮੷͋Γ • DAML͸Haskell/ScalaͰ։ൃ͞Ε͍ͯΔɺ
 εϚʔτίϯτϥΫτهड़ݴޠ • DAMLͷ։ൃʹ͓͍ͯGHC Pluginsͱ͍͏ܗͰ RecordDotSyntaxͱ΄΅ಉ͡ػೳ͕࢖ΘΕ͍ͯΔ

7. ఏҊͯ͠Δͷ΋DAMLͷਓ https://github.com/ghc-proposals/ghc-proposals/pull/282

8. PR΁ͷ൓Ԡ https://github.com/ghc-proposals/ghc-proposals/pull/282#issuecomment-540968106 *
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9. PR΁ͷ൓Ԡ 5IF
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10. PR΁ͷ൓Ԡ 5IJT
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    OPOTFOTF https://github.com/ghc-proposals/ghc-proposals/pull/282#issuecomment-541460439

11. > :t (.age) (.age) :: Person -> Int > :t

    (. age) (. age) :: (Int -> c) -> Person -> c ۭനͷ༗Γແ͠Ͱ͜͜·Ͱҙຯ͕มΘΔͷ͸
    ॳ৺ऀʹ͸೉͘͠ͳ͍ʁ

12. ࠓͷεςʔλε https://github.com/ghc-proposals/ghc-proposals/pull/282#issuecomment-559259994 8JUI
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13. ະղܾ໰୊ https://twitter.com/ndm_haskell/status/1190680324495302658

14. ͋Ε͜Ε

15. f a.b.c x ͷύʔε f a.foo.bar.baz.quux 12 ͸
    f (a.foo.bar.baz.quux)

    12 ͱධՁ͞ΕΔ
    ((f a).foo.bar.baz.quux) 12
    Ͱ͸ͳ͍ https://github.com/shayne-fletcher-da/ghc-proposals/blob/record-dot-syntax/proposals/0000-record-dot-syntax.md#record-selection

16. Lens͸ʁ • f $ record ^. field ͕ f record.field

    ͱॻ͚Δ • Lens͸ෳࡶա͗Δ… • Lensͱ͸໊લۭ͕ؒҟͳΔͷͰҰॹʹ࢖͑Δ https://github.com/shayne-fletcher-da/ghc-proposals/blob/record-dot-syntax/proposals/0000-record-dot-syntax.md#alternatives-to-this-proposal

17. ͜͏͍͏දه͸ແ͍ • ߋ৽ʹؔ͢Δߏจ • a{field * 2} • a{field <-

    (*2)} • a{field * = 2} • ߋ৽ʹؔ͢ΔηΫγϣϯ • ({a=}) • ({a=b}) • (.lbl=) https://github.com/shayne-fletcher-da/ghc-proposals/blob/record-dot-syntax/proposals/0000-record-dot-syntax.md#alternatives-within-this-proposal

18. Ҏ্