Programmation en Clojique

Prolog is this weird old language that established the paradigm of logic programming. Once heralded as the solution to all AI problems, it is now considered a niche language. Luckily, many languages have adopted ideas from Prolog, such as Clojure with core.logic. In this talk, I would like to introduce Prolog’s programming model and showcase some programming domains in which it allows for very concise, elegant programs.

Transcript

1. P r o g r a m m a t i o n
   e n C l o g i q u e
   L a r s H u p e l
   : c l o j u r e D
   2 0 2 0 - 0 2 - 2 9
   

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2. (defne presentation [orateur]
   ([:lars]
   (fresh [questions]
   (blague :drole) #_(rire)
   (introduction :corelogic)
   (fonctions :cool)
   (audience questions)
   (repondre questions))))
   

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3. P r o g r a m m a t i o n
   e n C l o g i q u e
   L a r s H u p e l
   : c l o j u r e D
   2 0 2 0 - 0 2 - 2 9
   

   View Slide

4. (defne presentation [speaker]
   ([:lars]
   (fresh [questions]
   (joke :funny) #_(laugh)
   (introduction :corelogic)
   (features :cool)
   (audience questions)
   (answer questions))))
   

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5. (defne presentation [speaker]
   ([:lars]
   (fresh [questions]
   (joke :funny) #_(laugh)
   (introduction :corelogic)
   (features :cool)
   (audience questions)
   (answer questions))))
   

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6. W h o i n v e n t e d l o g i c
   p r o g r a m m i n g ?
   “ 1 . T h e w o r l d i s e v e r y t h i n g t h a t i s t h e c a s e .
   1 .1 T h e w o r l d i s t h e t o t a l i t y o f f a c t s , n o t o f t h i n g s .
   1 .1 1 T h e w o r l d i s d e t e r m i n e d b y t h e f a c t s , a n d b y t h e s e b e i n g a l l t h e
   f a c t s .
   ”
   

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7. W h o i n v e n t e d l o g i c
   p r o g r a m m i n g ?
   “ 1 . T h e w o r l d i s e v e r y t h i n g t h a t i s t h e c a s e .
   1 .1 T h e w o r l d i s t h e t o t a l i t y o f f a c t s , n o t o f t h i n g s .
   1 .1 1 T h e w o r l d i s d e t e r m i n e d b y t h e f a c t s , a n d b y t h e s e b e i n g a l l t h e
   f a c t s .
   ”
   – L u d w i g W i t t g e n s t e i n , 1 9 1 8
   

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8. (defne presentation [speaker]
   ([:lars]
   (fresh [questions]
   (joke :funny) #_(laugh)
   (introduction :corelogic)
   (features :cool)
   (audience questions)
   (answer questions))))
   

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9. W h o i n v e n t e d P r o l o g ?
   • a p p e a r e d i n t h e e a r l y 7 0 s i n F r a n c e
   • o r i g i n a l d e v e l o p e r s : A l a i n C o l m e r a u e r a n d P h i l i p p e R o u s s e l
   • u s e d t h e .pl e x t e n s i o n b e f o r e P e r l
   • r a d i c a l l y d i f f e r e n t p r o g r a m m i n g p a r a d i g m
   • t h i s t a l k : u s i n g c o r e . l o g i c s y n t a x
   

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10. A b r i e f p r i m e r o n P r o l o g
    1 . P r o l o g p r o g r a m s a r e s e q u e n c e s o f r u l e s ( o r c l a u s e s ) .
    

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11. A b r i e f p r i m e r o n P r o l o g
    1 . P r o l o g p r o g r a m s a r e s e q u e n c e s o f r u l e s ( o r c l a u s e s ) .
    2 . R u l e s c a n h a v e a r g u m e n t s .
    

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12. A b r i e f p r i m e r o n P r o l o g
    1 . P r o l o g p r o g r a m s a r e s e q u e n c e s o f r u l e s ( o r c l a u s e s ) .
    2 . R u l e s c a n h a v e a r g u m e n t s .
    3 . R u l e s c a n h a v e c o n d i t i o n s .
    

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13. A b r i e f p r i m e r o n P r o l o g
    1 . P r o l o g p r o g r a m s a r e s e q u e n c e s o f r u l e s ( o r c l a u s e s ) .
    2 . R u l e s c a n h a v e a r g u m e n t s .
    3 . R u l e s c a n h a v e c o n d i t i o n s .
    4 . P r o g r a m s c a n b e q u e r i e d .
    

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14. A b r i e f p r i m e r o n P r o l o g
    1 . P r o l o g p r o g r a m s a r e s e q u e n c e s o f r u l e s ( o r c l a u s e s ) .
    2 . R u l e s c a n h a v e a r g u m e n t s .
    3 . R u l e s c a n h a v e c o n d i t i o n s .
    4 . P r o g r a m s c a n b e q u e r i e d .
    5 . A n y t h i n g t h a t i s n o t i n t h e p r o g r a m i s n o t t r u e .
    

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15. E r l a n g , i n s p i r e d b y P r o l o g
    “ T h e f i r s t i n t e r p r e t e r w a s a s i m p l e P r o l o g m e t a i n t e r p r e t e r w h i c h
    a d d e d t h e n o t i o n o f a s u s p e n d a b l e p r o c e s s t o P r o l o g . . . [ i t ] w a s r a p i d l y
    m o d i f i e d ( a n d r e - w r i t t e n ) . . .
    ”
    – A r m s t r o n g , V i r d i n g , W i l l i a m s : U s e o f P r o l o g f o r d e v e l o p i n g a n e w p r o g r a m m i n g l a n g u a g e
    

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16. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    

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17. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    I n t e r p r e t e r
    => (run* (hi))
    (_0)
    

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18. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    I n t e r p r e t e r
    => (run* (hi))
    (_0)
    (defn hello [x]
    (== x :world))
    

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19. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    I n t e r p r e t e r
    => (run* (hi))
    (_0)
    (defn hello [x]
    (== x :world))
    => (run* [_] (hello :world))
    (_0)
    

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20. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    I n t e r p r e t e r
    => (run* (hi))
    (_0)
    (defn hello [x]
    (== x :world))
    => (run* [_] (hello :world))
    (_0)
    => (run* [_] (hello :coworld))
    ()
    

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21. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    I n t e r p r e t e r
    => (run* (hi))
    (_0)
    (defn hello [x]
    (== x :world))
    => (run* [_] (hello :world))
    (_0)
    => (run* [_] (hello :coworld))
    ()
    

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22. H e l l o W o r l d !
    P r o g r a m
    (defn hi [])
    I n t e r p r e t e r
    => (run* (hi))
    (_0)
    (defn hello [x]
    (== x :world))
    => (run* [_] (hello :world))
    (_0)
    => (run* [_] (hello :coworld))
    ()
    => (run* [x] (hello x))
    (:world)
    

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23. A s m a l l p r o g r a m
    F a c t s
    (defne location [place in]
    ([:munich :germany])
    ([:augsburg :germany])
    ([:germany :europe])
    ([:london :unitedkingdom])
    ([:unitedkingdom :europe]))
    

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24. A s m a l l p r o g r a m
    F a c t s
    (defne location [place in]
    ([:munich :germany])
    ([:augsburg :germany])
    ([:germany :europe])
    ([:london :unitedkingdom])
    ([:unitedkingdom :europe]))
    EU Customs Union
    Council of Europe
    European Union
    EEA
    BSEC
    Eurozone
    Benelux
    Baltic Assembly
    EFTA
    GUAM
    CEFTA
    Schengen Area
    Union State
    Nordic
    Council
    Visegrád
    Group
    Common
    Travel Area
    Monetary agreement
    with the EU
    

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25. A s m a l l p r o g r a m
    F a c t s
    (defne location [place in]
    ([:munich :germany])
    ([:augsburg :germany])
    ([:germany :europe])
    ([:london :unitedkingdom])
    ([:unitedkingdom :europe]))
    

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26. A s m a l l p r o g r a m
    F a c t s
    (defne location [place in]
    ([:munich :germany])
    ([:augsburg :germany])
    ([:germany :europe])
    ([:london :unitedkingdom])
    ([:unitedkingdom :europe]))
    R u l e s
    (defn neighbour [x y]
    (fresh [z]
    (location x z)
    (location y z)))
    

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27. A s m a l l p r o g r a m
    F a c t s
    (defne location [place in]
    ([:munich :germany])
    ([:augsburg :germany])
    ([:germany :europe])
    ([:london :unitedkingdom])
    ([:unitedkingdom :europe]))
    R u l e s
    (defn is-in [x y]
    (conde
    [(location x y)]
    [(fresh (z)
    (location x z)
    (is-in z y))]))
    

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28. (defne presentation [speaker]
    ([:lars]
    (fresh [questions]
    (joke :funny) #_(laugh)
    (introduction :corelogic)
    (features :cool)
    (audience questions)
    (answer questions))))
    

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29. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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30. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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31. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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32. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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33. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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34. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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35. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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36. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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37. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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38. B a c k t r a c k i n g
    (defn best-boy [x]
    (fresh [y]
    (dog :good x)
    (colour :dark_brown x)
    (behind x y)
    (colour :light_brown y)))
    

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39. B i - d i r e c t i o n a l c o m p u t i n g
    f
    : I
    → O
    

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40. B i - d i r e c t i o n a l c o m p u t i n g
    f
    : I
    → O
    

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41. B i - d i r e c t i o n a l c o m p u t i n g
    f
    : I
    → O
    R
    : (I
    × O
    ) → {0
    , 1
    }
    

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42. B i - d i r e c t i o n a l c o m p u t i n g
    C l o j u r e
    (concat xs ys)
    

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43. B i - d i r e c t i o n a l c o m p u t i n g
    C l o j u r e
    (concat xs ys)
    c o r e . l o g i c
    (appendo xs ys zs)
    

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44. N o t a s i l v e r b u l l e t . . .
    H o w t o r e v e r s e flatten?
    

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45. W h a t a b o u t n u m b e r s ?
    => (run* [x y] (membero x [1 2 3]) (== y 2) (> x y))
    

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46. W h a t a b o u t n u m b e r s ?
    => (run* [x y] (membero x [1 2 3]) (== y 2) (> x y))
    

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47. W h a t a b o u t n u m b e r s ?
    => (run* [x y] (membero x [1 2 3]) (== y 2) (> x y))
    => (require '[clojure.core.logic.fd :as fd])
    => (run* [x y] (membero x [1 2 3]) (== y 2) (fd/> x y))
    ([3 2])
    

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48. F a c t d a t a b a s e s
    H o w t o m o d e l f a c t s e v o l v i n g o v e r t i m e ?
    

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49. F a c t d a t a b a s e s
    H o w t o m o d e l f a c t s e v o l v i n g o v e r t i m e ?
    S e l f - m o d i f y i n g c o d e ?
    

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50. F a c t d a t a b a s e s
    H o w t o m o d e l f a c t s e v o l v i n g o v e r t i m e ?
    S e l f - m o d i f y i n g c o d e ?
    J u s t l i k e i n S Q L !
    

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51. P L D B
    (pldb/db-rel location p q)
    (def facts
    (pldb/db
    [location :munich :germany]
    [location :augsburg :germany]
    [location :germany :europe]
    [location :london :unitedkingdom]
    [location :unitedkingdom :europe]))
    

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52. P L D B a s r e a l
    d a t a b a s e
    • d a t a m o d e l i s s i m i l a r t o S Q L :
    s e t s o f t u p l e s ( “ r e l a t i o n s ” )
    • P L D B i s s t a t i c & i m m u t a b l e
    

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53. C o n s t r a i n t s o l v i n g
    P u z z l e
    T h e r e a r e f i v e h o u s e s .
    1 . T h e E n g l i s h p e r s o n l i v e s i n t h e r e d h o u s e .
    2 . T h e S w e d i s h p e r s o n o w n s a d o g .
    3 . T h e D a n i s h p e r s o n l i k e s t o d r i n k t e a .
    4 . T h e g r e e n h o u s e i s l e f t t o t h e w h i t e h o u s e .
    5 . T h e o w n e r o f t h e g r e e n h o u s e d r i n k s c o f f e e .
    6 . . . .
    

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54. G r a m m a r s
    

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55. G r a m m a r s
    

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56. G r a m m a r s
    

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57. G r a m m a r s
    (def-->e det [d]
    ([[:d 'the]] '[the])
    ([[:d 'a]] '[a]))
    (def-->e noun-phrase [n]
    ([[:np ?d ?n]]
    (det ?d) (noun ?n)))
    

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58. P r o l o g i s f o r p a r s i n g ?
    “ T h e p r o g r a m m i n g l a n g u a g e . . . w a s b o r n o f a p r o j e c t a i m e d n o t a t
    p r o d u c i n g a p r o g r a m m i n g l a n g u a g e b u t a t p r o c e s s i n g n a t u r a l l a n -
    g u a g e s ; i n t h i s c a s e , F r e n c h .
    ”
    – C o l m e r a u e r , R o u s s e l : T h e B i r t h o f P r o l o g
    

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59. P r o l o g i s f o r p a r s i n g ?
    “ T h e p r o g r a m m i n g l a n g u a g e . . . w a s b o r n o f a p r o j e c t a i m e d n o t a t
    p r o d u c i n g a p r o g r a m m i n g l a n g u a g e b u t a t p r o c e s s i n g n a t u r a l l a n -
    g u a g e s ; i n t h i s c a s e , F r e n c h .
    ”
    – C o l m e r a u e r , R o u s s e l : T h e B i r t h o f P r o l o g
    

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60. (defne presentation [speaker]
    ([:lars]
    (fresh [questions]
    (joke :funny) #_(laugh)
    (introduction :corelogic)
    (features :cool)
    (audience questions)
    (answer questions))))
    

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61. Q & A
    L a r s H u p e l
    �
    l a r s . h u p e l @ i n n o q . c o m
    � @ l a r s r _ h
    w w w . i n n o q . c o m
    i n n o Q D e u t s c h l a n d G m b H
    K r i s c h e r s t r . 1 0 0
    4 0 7 8 9 M o n h e i m a . R h .
    G e r m a n y
    + 4 9 2 1 7 3 3 3 6 6 - 0
    O h l a u e r S t r . 4 3
    1 0 9 9 9 B e r l i n
    G e r m a n y
    L u d w i g s t r . 1 8 0 E
    6 3 0 6 7 O f f e n b a c h
    G e r m a n y
    K r e u z s t r . 1 6
    8 0 3 3 1 M ü n c h e n
    G e r m a n y
    c / o W e W o r k
    H e r m a n n s t r a s s e 1 3
    2 0 0 9 5 H a m b u r g
    G e r m a n y
    i n n o Q S c h w e i z G m b H
    G e w e r b e s t r . 1 1
    C H - 6 3 3 0 C h a m
    S w i t z e r l a n d
    + 4 1 4 1 7 4 3 0 1 1 1
    A l b u l a s t r . 5 5
    8 0 4 8 Z ü r i c h
    S w i t z e r l a n d
    

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62. L A R S H U P E L
    C o n s u l t a n t
    i n n o Q D e u t s c h l a n d G m b H
    L a r s e n j o y s p r o g r a m m i n g i n a v a r i e t y o f l a n -
    g u a g e s , i n c l u d i n g S c a l a , H a s k e l l , a n d R u s t . H e i s
    k n o w n a s a f r e q u e n t c o n f e r e n c e s p e a k e r a n d o n e
    o f t h e f o u n d e r s o f t h e T y p e l e v e l i n i t i a t i v e w h i c h
    i s d e d i c a t e d t o p r o v i d i n g p r i n c i p l e d , t y p e - d r i v e n
    S c a l a l i b r a r i e s .
    

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63. I m a g e s o u r c e s
    • T i t l e ( m a p ) : https://pixabay.com/photos/world-europe-map-connections-1264062/
    • S h i b a r o w : https://www.pinterest.de/pin/424112489894679416/
    • S h i b a w i t h m l e m : https://www.reddit.com/r/mlem/comments/6tc1of/shibe_doing_a_mlem/
    • H a p p y d o g : https://www.rover.com/blog/is-my-dog-happy/
    • K i d w i t h c r o s s e d a r m s : https:
    //www.psychologytoday.com/us/blog/spycatcher/201410/9-truths-exposing-myth-about-body-language
    • N o a m C h o m s k y : https://en.wikipedia.org/wiki/File:Noam_Chomsky_Toronto_2011.jpg
    • A l a i n C o l m e r a u e r : https://de.wikipedia.org/wiki/Datei:A-Colmerauer_web-800x423.jpg
    • J o e A r m s t r o n g : E r l a n g , t h e M o v i e
    • S i g n a t u r e s : http://www.swi-prolog.org/pldoc/man?section=preddesc
    • Z e b r a p u z z l e : S t a c k O v e r f l o w c o n t r i b u t o r s ( https://stackoverflow.com/q/11122814/4776939)
    • O w l : https://www.theloop.ca/angry-owl-terrorizes-oregon-joggers/
    • C l o c k : https://pixabay.com/photos/clock-alarm-alarm-clock-dial-time-1031503/
    • F i l e s : https://pixabay.com/photos/files-ddr-archive-1633406/
    

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