Intro to Clojure

Slides of my Lecture in the Academic Computer Science week - UFF 2015

Transcript

1. CLOJURE
   Intro to
   @raphamundi
   

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3. Raphael Amorim
   This is me :P
   

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4. WHAT’S CLOJURE
   ?
   

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5. WHAT’S CLOJURE?
   Clojure is a dynamic programming
   language that targets the Java Virtual
   Machine (and the CLR, and JavaScript).
   

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6. WHO’S USING CLOJURE?
   Akamai, Appvise, Citigroup, Amazon,
   eBay, Heroku, Groupon, Netflix, Nubank,
   Salesforce, Walmart Labs, Zendesk […]
   http://clojure.org/Companies
   

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7. TAKING NOTES.
   

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8. - Started in 2007
   
   - Created by Rich Hickey
   
   - Under Eclipse Public License
   TAKING NOTES.
   

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9. “ Clojure is a dialect of Lisp, and shares with
   Lisp the code-as-data philosophy and a
   powerful macro system. Clojure is predominantly
   a functional programming language ”
   TAKING NOTES.
   

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10. FUNCIONAL PARADIGM?
    

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11. Back to the Past.
    

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12. λ - 1930
    The Lambda Calculus Appears
    Back to the Past.
    

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13. Lisp - 1958
    Introduced a programming language able
    to deal with mathematical notation
    Back to the Past.
    

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14. Lisp - 1958
    Introduced a programming language able
    to deal with mathematical notation
    * IPL (Information Processing Language) is sometimes cited as the first
    computer-based functional programming language. First appeared in 1956.
    Back to the Past.
    

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15. “Can Programming Be Liberated
    from the von Neumann Style?” - 1978
    John Backus (FORTRAN creator) criticizes hardware architecture
    based on von Neuman model.
    Back to the Past.
    

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16. The Boom- 1980
    Innovative techniques have been proposed, such as: Lazy Evaluation
    Emergence of other languages such as: Lazy ML, Orwell, Alfl, Id,
    Clean, Ponder e Daisy
    Back to the Past.
    

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17. Definitions
    

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18. Treats computation as the evaluation of mathematical
    functions and avoids changing-state and mutable data.
    

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19. So…
    

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20. Take values and return values.
    

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21. Same argument, same result.
    

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22. Testing is easier, because there’s
    no state.
    

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23. NO SIDE EFFECTS.
    

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24. NO SIDE EFFECTS.
    Almost (e.g: I/O)
    

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25. Syntax?
    

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26. - Numbers ( 1, 3, 5, 85 )
    
    - Character ( \h, \r, \a )
    
    - String ( “barbante” )
    
    - Boolean ( true, false )
    
    - Symbol ( ‘a, ‘b, ‘c )
    
    

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27. - Keywords ( :bad, :cool, :ugly )
    
    - null ( nil )
    

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28. Collections (all of them are immutable)
    
    - Lists ( '(1 2 3 4) )
    
    - sequential and counted, not associative
    
    - first and rest
    
    - Vector ( [ 1 2 101 85 ] )
    
    - sequential, counted and associative
    
    - access by key
    
    

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29. Collections (all of them are immutable)
    
    - Maps ( { “raphael” 20, “richard" 25, “chuck” 99 } )
    
    - counted and associative, not sequential
    
    - access by key
    
    - Sets ( #{“hugo” “raphael” “vianna”} )
    
    - counted, not sequential, not associative
    
    - lookup for containment
    
    

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30. Clojure REPL
    

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31. There’s NO interpreter
    

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32. "Laziness is a virtue"
    

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33. "Laziness is a virtue"
    

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34. Clojure Concurrency?
    

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35. Clojure Concurrency
    

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36. Clojure Concurrency
    

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37. Today…
    To avoid Deadlocks:
    

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38. Timeout and Retry?
    Specific Lock Order?
    Coarse Locks?
    

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39. “ Locks are the Enemy ”
    

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40. STM
    Software Transactional Memory
    

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41. NO BLOCKING
    

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42. NO LOCKS
    

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43. PERSISTENT COLLECTIONS
    

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44. Clojure IS much more…
    

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45. • Clojure:Functional Concurrency for the JVM - Howard M. Lewis Ship
    • Clojure: A dynamic programming language for the JVM - Rich Hickey
    • Intro to Clojure by Balint Erdi ( https://speakerdeck.com/balint/intro-
    to-clojure )
    • Clojure Intro ( http://www.slideshare.net/thnetos/clojure-intro )
    • Introduction to Clojure by Renzo Borgatti ( http://pt.slideshare.net/
    reborg/introduction-to-clojure-13679039 )
    References
    

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46. • http://www.braveclojure.com/getting-started/
    References
    

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47. Thanks!!
    @raphamundi
    

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