Practical REPL-driven Development with Clojure

Enjoy REPL-driven development with Clojure! (*> ᴗ •*)ゞ

Transcript

1. Practical REPL-driven Development with Clojure
2. Self-introduction /laʒenɔʁɛ̃k/ カマイルカ lagénorhynque (defprofile lagénorhynque :name "Kent OHASHI" :languages [Clojure Haskell Python Scala English français Deutsch русский] :interests [programming language-learning mathematics] :contributing [github.com/japan-clojurians/clojure-site-ja])
3. Contents 1. Clojure Quick Intro 2. Leiningen 3. Clojure REPL 4. Lisp Editing 5. REPL-driven Development in Practice
4. Clojure Quick Intro
5. Clojure Lisp S-expressions, macros, etc. REPL-driven development functional programming language dynamic language JVM language (cf. ClojureScript) ⇒ simple and powerful language
6. literals type example string "abc" character \a number 1, 2.0, 3N, 4.5M, 6/7, 8r10 boolean true, false nil nil keyword :a, :user/a, ::a, ::x/a symbol 'a, 'user/a, `a, `x/a
7. type example list '(1 2 3), '(+ 1 2 3) vector [1 2 3] set #{1 2 3} map {:a 1 :b 2}, #:user{:a 1 :b 2}, #::{:a 1 :b 2}, #::x{:a 1 :b 2} function (fn [x] (* x x))
8. the syntax operator function macro special form (op arg1 arg2 ... argn)
9. Leiningen
10. lein repl starts Clojure REPL $ lein repl nREPL server started on port 49482 on host 127.0.0.1 - nrepl://1 27.0.0.1:49482 REPL-y 0.3.7, nREPL 0.2.12 Clojure 1.8.0 Java HotSpot(TM) 64-Bit Server VM 1.8.0_121-b13 Docs: (doc function-name-here) (find-doc "part-of-name-here") Source: (source function-name-here) Javadoc: (javadoc java-object-or-class-here) Exit: Control+D or (exit) or (quit) Results: Stored in vars *1, *2, *3, an exception in *e user=>
11. lein new generates a new Clojure project generate a project with app template cf. $ lein new app clj-demo Generating a project called clj-demo based on the 'app' template lein-template
12. $ tree clj-demo/ clj-demo/ ├── CHANGELOG.md ├── LICENSE ├── README.md ├── doc │ └── intro.md ├── project.clj ├── resources ├── src │ └── clj_demo │ └── core.clj └── test └── clj_demo └── core_test.clj
13. lein run runs -main function $ cd clj-demo/ $ lein run Hello, World!
14. cf. src/clj_demo/core.clj (ns clj-demo.core (:gen-class)) (defn -main "I don't do a whole lot ... yet." [& args] (println "Hello, World!"))
15. lein test runs tests $ lein test lein test clj-demo.core-test lein test :only clj-demo.core-test/a-test FAIL in (a-test) (core_test.clj:7) FIXME, I fail. expected: (= 0 1) actual: (not (= 0 1)) Ran 1 tests containing 1 assertions. 1 failures, 0 errors. Tests failed.
16. cf. test/clj_demo/core_test.clj (ns clj-demo.core-test (:require [clojure.test :refer :all] [clj-demo.core :refer :all])) (deftest a-test (testing "FIXME, I fail." (is (= 0 1))))
17. lein uberjar creates jar files $ lein uberjar Compiling clj-demo.core Created /Users/k.ohashi/code/clj-demo/target/uberjar/clj-demo-0. 1.0-SNAPSHOT.jar Created /Users/k.ohashi/code/clj-demo/target/uberjar/clj-demo-0. 1.0-SNAPSHOT-standalone.jar $ java -jar target/uberjar/clj-demo-0.1.0-SNAPSHOT-standalone.ja r Hello, World!
18. Clojure REPL
19. evaluate expressions clj-demo.core=> (map inc [0 1 2]) (1 2 3) clj-demo.core=> (println (map inc [0 1 2])) (1 2 3) nil
20. clojure.repl/doc prints documentation clj-demo.core=> (doc map) ------------------------- clojure.core/map ([f] [f coll] [f c1 c2] [f c1 c2 c3] [f c1 c2 c3 & colls]) Returns a lazy sequence consisting of the result of applying f to the set of first items of each coll, followed by applying f to the set of second items in each coll, until any one of the colls is exhausted. Any remaining items in other colls are ignored. Function f should accept number-of-colls arguments. Returns a transducer when no collection is provided. nil
21. clojure.repl/source prints source code clj-demo.core=> (source map) (defn map "Returns a lazy sequence consisting of the result of applying f to the set of first items of each coll, followed by applying f to the set of second items in each coll, until any one of the colls is exhausted. Any remaining items in other colls are ignored. Function f should accept number-of-colls arguments. Returns a transducer when no collection is provided." {:added "1.0" :static true} ([f] (fn [rf] (fn ([] (rf)) ([result] (rf result)) ([result input] (rf result (f input))) ([result input & inputs] (rf result (apply f input inputs))))))
22. clojure.core/*1, *2, *3 special vars bound to the most recent values printed clj-demo.core=> 21 21 clj-demo.core=> 2 2 clj-demo.core=> (* *2 *1) 42
23. clojure.core/*e special var bound to the most recent exception caught by the REPL clj-demo.core=> (+ 1 "2") ClassCastException java.lang.String cannot be cast to java.lang.Number clj-demo.core=> *e #error { :cause "java.lang.String cannot be cast to java.lang.Number" :via [{:type java.lang.ClassCastException :message "java.lang.String cannot be cast to java.lang.Number" :at [clojure.lang.Numbers add "Numbers.java" 128]}] :trace [[clojure.lang.Numbers add "Numbers.java" 128] [clojure.lang.Numbers add "Numbers.java" 3640] [clj_demo.core$eval1328 invokeStatic "form-init3161334546666357405.cl [clj_demo.core$eval1328 invoke "form-init3161334546666357405.clj" 1] [clojure.lang.Compiler eval "Compiler.java" 6927] [clojure.lang.Compiler eval "Compiler.java" 6890] [clojure.core$eval invokeStatic "core.clj" 3105]
24. search documentation clojure.repl/find-doc clojure.repl/apropos clojure.java.javadoc/javadoc
25. Lisp editing
26. Lisp editing plugins Parinfer ParEdit
27. Parinfer automatically adjust parentheses when editing indentation (Indent mode), indentation when editing parentheses (Paren mode)
28. e.g. Atom with Parinfer
29. (
30. defn␣my-map␣ [ f␣coll
31. ⌘-<RET> <TAB>
32. (
33. when-let␣ [ s␣ ( seq␣coll
34. ⌘-<RET> <TAB>
35. (
36. cons␣ ( f␣ ( first␣s
37. ⌘-<RET> <TAB> <TAB>
38. (
39. my-map␣f␣ ( rest␣s
40. <up> <up> ⌘-<left>
41. (
42. lazy-seq <RET>
43. <down> <TAB> <down> <TAB>
44. ParEdit semi-automatically adjust parentheses and indentation cf. Smartparens
45. e.g. Emacs with ParEdit
46. (
47. defn␣my-map␣ [ f␣coll
48. )
49. <RET>
50. (
51. when-let␣ [ s␣ ( seq␣coll
52. ) )
53. <RET> (
54. cons␣ ( f␣ ( first␣s
55. ) )
56. <RET>
57. ( my-map␣f␣ ( rest␣s
58. <C>-<M>-u <C>-<M>-u <C>-<M>-u <C>-<M>-u
59. <M>-(
60. lazy-seq <RET>
61. REPL-driven Development in Practice
62. Course A: Course B: Clojure Koans 4Clojure
63. Clojure Koans cf. ClojureScript Koans
64. Clone the repository $ git clone git://github.com/functional-koans/clojure-koans.git Cloning into 'clojure-koans'... remote: Counting objects: 1590, done. remote: Compressing objects: 100% (7/7), done. remote: Total 1590 (delta 2), reused 4 (delta 1), pack-reused 15 80 Receiving objects: 100% (1590/1590), 269.87 KiB | 651.00 KiB/s, done. Resolving deltas: 100% (755/755), done.
65. Run koans $ cd clojure-koans/ $ lein koan run Starting auto-runner... Considering /Users/k.ohashi/code/clojure-koans/src/koans/01_equa lities.clj... Now meditate upon /Users/k.ohashi/code/clojure-koans/src/koans/0 1_equalities.clj --------------------- Assertion failed! clojure.lang.ExceptionInfo: We shall contemplate truth by testin g reality, via equality (= __ true) {:line 6}, compiling:(/Users/k.ohashi/code/clojure-k oans/src/koans/01_equalities.clj:4:1)
66. Open a source le with your favourite editor $ emacs src/koans/01_equalities.clj
67. Start Clojure REPL
68. Evaluate S-expressions
71. Send S-expressions to REPL
77. Save changes and check the meditation result ... Now meditate upon /Users/k.ohashi/code/clojure-koans/src/koans/0 1_equalities.clj --------------------- Assertion failed! clojure.lang.ExceptionInfo: You can test equality of many things (= (+ 3 4) 7 (+ 2 __)) {:line 12}, compiling:(/Users/k.ohashi/co de/clojure-koans/src/koans/01_equalities.clj:4:1)
78. 4Clojure
79. Open a new buffer with your favourite editor $ emacs clj-demo/src/clj_demo/4clojure/problem22.clj
80. Start Clojure REPL
81. e.g. Count a Sequence Problem #22 Write a function which returns the total number of elements in a sequence. (= (__ '(1 2 3 3 1)) 5) (= (__ "Hello World") 11) (= (__ [[1 2] [3 4] [5 6]]) 3) (= (__ '(13)) 1) (= (__ '(:a :b :c)) 3) Special Restrictions: count
82. Write a function
83. Evaluate S-expressions
89. Send S-expressions to REPL
96. Run your solution on the problem page (fn my-count [coll] (reduce (fn [n _] (inc n)) 0 coll))
97. Enjoy REPL-driven development!
98. Further Reading
99. Clojure & ClojureScript build tool Clojure ClojureScript Leiningen
100. editor plugins/settings Clojure develompent Emacs cf. CIDER Clojure 初⼼者のための Emacs 設定作りました 新: Emacs を使うモダンな Clojure 開発環境 Spacemacs Clojure layer Clojure development with Spacemacs & Cider
101. IntelliJ IDEA Atom Cursive IntelliJ IDEA と Cursive で始める — Clojure の⽇ 本語ガイド Atom Clojure Setup ClojureやりたいけどEmacsは厳しい⼈のための proto-repl⼊⾨
102. Vim Visual Studio Code Sublime Text fireplace.vim clojureVSCode SublimeClojureSetup
103. Lisp editing Parinfer ParEdit ParEdit チュートリアル Paredit Cheatsheet The Animated Guide to Paredit Lispってどう書くの? - Qiita Smartparens
104. REPL-driven development Re:REPL-Driven Development REPL Driven Development REPL Driven Development and Testing in Clojure