Clojureの基礎 〜マクロ編〜

2016/6/11 プログラミング言語基礎勉強会のLT発表資料です。

Transcript

1. $MPKVSFͷجૅ
   ϓϩάϥϛϯάݴޠجૅษڧձ
   2016/06/11
   @athos0220
   

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2. ࣗݾ঺հ
   ‣ 5XJUUFS!BUIPT
   ‣ χϟϯύε ג
   ॴଐ
   ‣ $MPKVSFίϯτϦϏϡʔλ
   

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3. $MPKVSFͷجૅΛ࡞Δ΋ͷ
   ࠓճ͸-JTQͱͯ͠ͷಛ௃ʹϑΥʔΧε
   -JTQ
   ؔ਺
   ϓϩάϥϛϯά
   ର࿩త
   ϓϩάϥϛϯά
   +7.
   

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4. -JTQ
   

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5. -JTQ
   ‣ લஔه๏͕ಛ௃
   ‣ ࠷ॳͷཁૉ͕ΦϖϨʔλɺͦΕҎ͕߱Ҿ਺
   ‣ ݴޠͷίΞ͕ඇৗʹγϯϓϧ
   (defn distance [x y]
   (sqrt (+ (* x x)
   (* y y))))
   

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6. -JTQ
   ‣ લஔه๏͕ಛ௃
   ‣ ࠷ॳͷཁૉ͕ΦϖϨʔλɺͦΕҎ͕߱Ҿ਺
   ‣ ݴޠͷίΞ͕ඇৗʹγϯϓϧ
   (defn distance [x y]
   (sqrt (+ (* x x)
   (* y y))))
   ΦϖϨʔλ Ҿ਺
   

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7. $PEFBT%BUB
   ‣ $MPKVSFίʔυΛ؆୯ʹσʔλͱͯ͠ѻ͑Δ
   ‣ $MPKVSFͷσʔλͰίʔυΛॻ͍͍ͯΔͱ΋͍͑Δ
   (read-string “(* x x)”)
   ;=> (* x x)
   

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8. $PEFBT%BUB
   ‣ $MPKVSFίʔυΛ؆୯ʹσʔλͱͯ͠ѻ͑Δ
   ‣ $MPKVSFͷσʔλͰίʔυΛॻ͍͍ͯΔͱ΋͍͑Δ
   (read-string “(* x x)”)
   ;=> (* x x)
   ͭͷγϯϘϧ Y Y͔ΒͳΔϦετ
   

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9. ॲཧܥͰͷྲྀΕ
   ίʔυ
   จࣈྻ
   
   ίʔυ
   σʔλ
   
   όΠτίʔυ
   

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10. ॲཧܥͰͷྲྀΕ
    ίʔυ
    จࣈྻ
    
    ίʔυ
    σʔλ
    
    όΠτίʔυ
    Ϧʔυ ίϯύΠϧ
    

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11. ϚΫϩ
    

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12. ϚΫϩͱ͸
    ‣ ίʔυ͔Βίʔυ΁ͷม׵Λఆٛ͢Δؔ਺
    ‣ Ϣʔβ͕޷͖ͳΑ͏ʹߏจΛఆٛͰ͖Δ࢓૊Έ
    ‣ ૉ๿ͳ͕Βڧྗͳϝλϓϩάϥϛϯάͷπʔϧ
    

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13. ॲཧܥͰͷྲྀΕ
    ίʔυ
    จࣈྻ
    
    ίʔυ
    σʔλ
    
    όΠτίʔυ
    Ϧʔυ ίϯύΠϧ
    

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14. ॲཧܥͰͷྲྀΕ
    ίʔυ
    จࣈྻ
    
    ίʔυ
    σʔλ
    
    όΠτίʔυ
    Ϧʔυ ίϯύΠϧ
    ϚΫϩల։
    

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15. PSΛఆٛͯ͠ΈΔ
    ‣ ͭΊͷࣜͷ஋͕USVFͩͬͨΒͭΊΛ୹བྷධՁ
    (or (expr-1) (expr-2))
    (let [v (expr-1)]
    (if v
    v
    (expr-2)))
    ల։
    

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16. PSΛఆٛͯ͠ΈΔ
    (defmacro or [expr1 expr2]
    `(let [v# ~expr1]
    (if v#
    v#
    ~expr2)))
    

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17. XJUIPQFOΛఆٛͯ͠ΈΔ
    ‣ +BWBͷUSZXJUISFTPVSDFTͷΑ͏ͳߏจ
    (with-open [f (reader “foo”)]
    (write-to-file f))
    (let [f (reader “foo”)]
    (try
    (write-to-file f)
    (finally
    (.close f))))
    ల։
    

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18. XJUIPQFOΛఆٛͯ͠ΈΔ
    (defmacro with-open [[name file] body]
    `(let [~name ~file]
    (try
    ~body
    (finally
    (.close ~name)))))
    

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19. ࣮։ൃͰͷϚΫϩ
    

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20. $PNQPKVSF
    ‣ $MPKVSFͷϧʔςΟϯάϥΠϒϥϦ
    (defroutes app-routes
    (GET “/” [] (index))
    (GET “/en” [] (index))
    (GET “/fr” [] (index-fr))
    (GET “/:greeting” [greeting]
    (view greeting)))
    

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21. DPSFNBUDI
    ‣ ύλʔϯϚονϥΠϒϥϦ
    (match inst
    [:mov z x] (recur (subst z x) insts)
    [:add z x y] (recur (do-op + z x y) insts)
    [:sub z x y] (recur (do-op - z x y) insts)
    [:push z x] (recur (push z x) insts)
    [:pop z] (recur (pop z) insts)
    [:jnz l] (if (:flag env)
    [l env]
    (recur env insts))
    [:jz l] (if (:flag env)
    (recur env insts)
    [l env] …)
    

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22. DPSFUZQFE
    ‣ ੩తܕνΣοΫϥΠϒϥϦ
    (ann new-file [(U URI String) -> File])
    (defn new-file [s]
    (if (string? s)
    (File. ^String s)
    (File. ^URI s)))
    

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23. DPSFBTZOD
    ‣ νϟωϧϕʔεͷඇಉظϓϩάϥϛϯάϥΠϒϥϦ
    (go
    (while true
    (let [v ((println v))))
    (go
    (loop [i 0]
    (>! ch i)
    (recur (inc i))))
    ड৴ଆίʔυ ૹ৴ଆίʔυ
    

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24. ͓·͚
    ‣ ϚΫϩ͸ඇৗʹڧྗͳͷͰѱ༻ͯ͠ݴޠࣗମΛେ෯
    ʹม͑ͯ͠·͏͜ͱ΋Ͱ͖Δ
    ‣ ྫʣΰϧϑ༻3VCZॲཧܥHPSVCZͷ໛฿
    ϝιουΛ୹ॖܗͰݺ΂Δ qFYNBUDIJOH
    
    - 1.up(10) {|i| p i}
    - [1,4,9].ew{|x,i| ps “#{i}:#{x}”}
    upto
    each_with_index puts
    

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25. HPDMPKVSF
    (doseq [[l n]
    (frequencies
    (map #(count (str %))
    (keys (ns-publics ’clojure.core))))]
    (printf “%2d %s\n” l (apply str (repeat n \*))))
    ΦϦδφϧͷίʔυ
    

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26. HPDMPKVSF
    (doseq [[l n]
    (frequencies
    (map #(count (str %))
    (keys (ns-publics ’clojure.core))))]
    (printf “%2d %s\n” l (apply str (repeat n \*))))
    (goclojure
    (dq [[l n]
    (qs
    (mp #(ou (sr %))
    (ks (nsb ’clojure.core))))]
    (pf “%2d %s\n” l (ay sr (rep n \*))))
    ΦϦδφϧͷίʔυ
    HPDMPKVSFΛ࢖ͬͯॻ͖׵͑ͨίʔυ
    

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27. ·ͱΊ
    ‣ -JTQͰ͋Δ͜ͱ͸$MPKVSFͷجૅΛ࡞Δཁૉͷͭ
    ‣ ϚΫϩ͸ڧྗͳϝλϓϩάϥϛϯάͷπʔϧ
    ‣ ࣮։ൃͰ࢖͑Δ͞·͟·ͳศརϚΫϩ͕͋Δ
    ‣ ͨͩ͠ཚ༻͗͢͠Δͱίʔυ͕ಡΊͳ͘ͳΔͷͰɺ
    ຊ౰ʹඞཁͳγνϡΤʔγϣϯΛݟۃΊΔ͜ͱ
    

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