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COMPONDO! UM! SISTEMA

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INTERATIVIDADE

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TESTABILIDADE

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FLEXIBILIDADE

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?

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f(x) → y

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x → ✨ → y

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{:users #{}}

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{:name "John Doe" :email "[email protected]"}

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✨ cadastro ✨

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{:users #{{:name "John Doe" :email "[email protected]"}}}

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DOMÍNIO

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{:title "Programing is Fn!" :body "..." :date #inst "2016-05-14" :tags #{:tech :clojure}}

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[{:title "How to Clojure"} {:title "Programing is Fn!"} {:title "Embracing Lisp"}]

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{:tech #{{:title "A"} {:title "B"}} :clojure #{{:title "B"}} :web #{{:title "A"} {:title "C"}}}

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N

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(transform input-data)

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(->> input-data (normalize) (transform) (serialize))

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(->> input-data (data/normalize) (data/transform) (json/serialize))

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FUNÇÕES PURAS

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aka, ✨

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(calculate-total order) ;; => order com total

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(deftest test-compute-order-total (let [order {:items [{:price 42.0} {:price 72.0}]}] (is (= (-> (calculate-total order) (:total)) 114.0))))

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(defn process-order [order] (-> order (calculate-shipping) (calculate-total) (include-gift)))

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(defn handler [{:keys [params]}] (->> (find-order (:id params)) (process-order) (render-response)))

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(defn subscriber [payload] (->> (parse-order payload) (process-order) (send-order-email)))

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(defn worker [file] (->> (orders-from file) (pmap process-order) (update-cache)))

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EFEITOS

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DI & POLIMORFISMO

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(send-welcome-mail customer)

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(defn send-welcome-mail [{:keys [name email]}] (send-mail mailer-config email (str "Bem-vindo " name "!"))

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(defn send-welcome-mail [{:keys [name email]}] (send-mail mailer-config email (str "Bem-vindo " name "!"))

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(defn send-welcome-mail [mailer {:keys [name email]}] (send-mail mailer email (str "Bem-vindo " name "!"))

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(defprotocol Mailer (send-mail [this address body])

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(defrecord WebMailer [endpoint api-key] Mailer (send-mail [this address body] ;; envia através de serviço )

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(defrecord StubMailer [sent] Mailer (send-mail [this address body] ;; armazena email em sent )

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(deftest test-sign-up-email (let [user {:email "[email protected]"} mailer (stub-mailer)] (sign-up-email mailer user) (is (= (:last-email mailer) {:to "[email protected]" :body "Welcome!"}))

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(deftest test-sign-up-email (let [user {:email "[email protected]"} mailer (stub-mailer)] (sign-up-email mailer user) (is (= (:last-email mailer) {:to "[email protected]" :body "Welcome!"}))

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(def server (start-server!))

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java.net.BindException: Address already in use

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RUNTIME

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COMPONENT com.stuartsierra/component

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(defrecord WebMailer [endpoint api-key]) ! (defn make-mailer [config] (map->WebMailer config))

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(defrecord Database [db-spec] component/Lifecycle (start [component] (assoc component :conn (make-conn! db-spec)) (stop [component] (release! (:conn component)) component) ! (defn make-database [db-spec] (->Database db-spec))

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(defrecord WebApp [db mailer] component/Lifecycle (start [component] (assoc component :handler (app-routes db mailer))) (stop [component] component)) ! (defn make-web-app [] (->WebApp))

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(defn new-system [] (component/system-map :db (make-database {:url "..."}) :mailer (make-mailer {:endpoint "..." :api-key "..."} :web-app (component/using (make-web-app) [:db :mailer])))

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(component/start (new-system))

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(defn new-system [] (merge (new-web-system) (new-worker-system)))

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(defn new-system [] (let [evs (async/chan)] (merge (new-web-system evs) (new-worker-system evs))))

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(defn dev-system [] (-> (new-system) (assoc :mailer (stub-mailer)) (assoc :migrator (db-migrator))))

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DADOS E TRANSFORMAÇÕES

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RUNTIME MÍNIMO! E GERENCIADO

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ITERATIVO &! TESTÁVEL &! FLEXÍVEL

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ANDREW ROSA @_andrewhr

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OBRIGADO! @_andrewhr

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REFERÊNCIAS • https://clojure.org • https://github.com/stuartsierra/component • https://github.com/clj-br • Clojure Brasil (Facebook)