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![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])](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-2-2048.jpg)
![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))](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-7-2048.jpg)
![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!"))](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-14-2048.jpg)
![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))))](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-16-2048.jpg)
![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](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-19-2048.jpg)
![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](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-20-2048.jpg)
![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))))))](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-21-2048.jpg)
![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]](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-23-2048.jpg)
![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](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-81-2048.jpg)
![Run your solution on the problem page (fn my-count [coll] (reduce (fn [n _] (inc n)) 0 coll))](https://image.slidesharecdn.com/practical-rdd-171013044057/75/Practical-REPL-driven-Development-with-Clojure-96-2048.jpg)
Uploaded byKent Ohashi
Practical REPL-driven Development with Clojure
This document introduces practical REPL-driven development with Clojure. It covers starting a Clojure REPL with Leiningen, evaluating expressions, viewing documentation, running tests and applications. It also discusses Lisp editing plugins like Parinfer and ParEdit that help with parentheses. Finally, it recommends resources on Clojure tools, editors, and REPL-driven development practices.
Practical REPL-driven Development with Clojure
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- 2. Self-introduction /laʒenɔʁɛ̃k/ カマイルカlagénorhynque (defprofile lagénorhynque :name "KentOHASHI" :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
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- 6. literals type example string "abc" charactera 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 '(12 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))
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- 10. lein repl starts Clojure REPL $ leinrepl 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. $ leinnew 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 $ cdclj-demo/ $ lein run Hello, World!
- 14. cf. src/clj_demo/core.clj (ns clj-demo.core (:gen-class)) (defn -main "Idon't do a whole lot ... yet." [& args] (println "Hello, World!"))
- 15. lein test runs tests $ leintest 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 $ leinuberjar 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!
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- 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) (defnmap "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))))))
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- 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]
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- 33. when-let␣ [ s␣( seq␣coll
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- 36. cons␣ ( f␣( first␣s
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- 43. <down> <TAB> <down><TAB>
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- 51. when-let␣ [ s␣( seq␣coll
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- 54. cons␣ ( f␣( first␣s
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- 57. ( my-map␣f␣ (rest␣s
- 58. <C>-<M>-u <C>-<M>-u <C>-<M>-u<C>-<M>-u
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- 64. Clone the repository $ git clonegit://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 $ emacssrc/koans/01_equalities.clj
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- 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)
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- 81. e.g. Count a Sequence Problem #22 Write a function which returns the total number of elements in a sequence. (= (__ '(12 3 3 1)) 5) (= (__ "Hello World") 11) (= (__ [[1 2] [3 4] [5 6]]) 3) (= (__ '(13)) 1) (= (__ '(:a :b :c)) 3) Special Restrictions: count
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- 96. Run your solution on the problem page (fn my-count [coll] (reduce(fn [n _] (inc n)) 0 coll))
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