![List (1 2 3 4 5)
Vector [1 2 3 4 5]
Map {:hello “world”}
Set #{1 2 3 4 5}
Data structures.](https://image.slidesharecdn.com/clojure-170808092103/85/Functional-web-development-with-Clojure-16-320.jpg)
![First attempt.
(def args {:tool "whip"
:garment "hat"
:nationality "american"
:location "jungle"})
(defn stringify [arg]
(update-in arg [0] name))
(defn splice-eqal [[key-part val-part]]
[key-part "=" val-part])
( ->> args
(vec)
(map stringify)
(map splice-equal)
(interpose "&")
(flatten)
(apply str))](https://image.slidesharecdn.com/clojure-170808092103/85/Functional-web-development-with-Clojure-22-320.jpg)
![Final result.
(defn format-arg
"Takes a vector of two items, where the first is
a keyword, which it turns into a string. It then
splices in an = between the two items, and fuses
them all together into a single string.”
[[key-part val-part]]
(str (name key-part) "=" val-part))
(defn make-string
"Takes a vector of args as strings, interposes ‘&’
between them and then mashes everything in it
together into a string."
[args]
( ->> args (interpose “&”) (apply str)))
(defn make-args
"Turns a map of args into a string."
[args]
(make-string (map format-arg args)))](https://image.slidesharecdn.com/clojure-170808092103/85/Functional-web-development-with-Clojure-23-320.jpg)
![Frontend development.
;; The state
(defonce app-state (atom 0))
;; Functions for modifying state
(defn increase-int []
(swap! app-state inc))
(defn decrease-int []
(swap! app-state dec))
;; The "template" for page content
(defn hello-world []
[:div
[:h1 (str "Current value in app-state: " @app-state)]
[:button {:on-click increase-int} "Inc"]
[:button {:on-click decrease-int} "Dec"]])
;; How we mount the "template"
(reagent/render-component [hello-world]
(. js/document (getElementById "app")))
The rendered result](https://image.slidesharecdn.com/clojure-170808092103/85/Functional-web-development-with-Clojure-25-320.jpg)
Functional (web) development with Clojure
- 3. Clojure is a strongly typed, dynamic, functional programming language that is defined in terms of its own persistent data structures. Introduction.
- 5. Complexity Introduction. Ability to comprehend complexity Normal person Smartest person in the world
- 6. Complexity Introduction. Have to bring the complex thing closer to us. The other way around doesn’t work.
- 8. Functional programming is only interesting to the degree it helps us achieve this goal. Clojure provides tools for the mind rather than for the machine. Introduction.
- 9. Persistent (immutable) data structures Object/stateless programming model Software Transactional Memory (STM) Powerful data processing and transformation tools Powerful data validation and testing tools Strongly and optionally typed Powerful (and easy) concurrency+parallelism Instant feedback-driven development Hosted on several platforms Features of the language.
- 10. Variables complects* time and state. Objects complects time, state and identity. Methods complects function and state. Syntax complects order and meaning. … The real features of the language. *To complect: to create complexity, usually by intertwining two or more unrelated concepts Values Values Functions Data …
- 11. In the browser, on NodeJS, on JVM, on .Net, on Android and in iOS. Same language. Piggybacks on other stuff. Acting like a symbiote, with direct, toll-less access to the underlying platform if need be. Symbiote.
- 13. Crossref Walmart The Daily Mail Akamai Circle CI Metabase Boeing Atlassian Netflix CitiGroup LinkedInThoughtWorks Cisco Nubank … In production. Apache Storm
- 15. String “Lol” Character & Number 267 Keyword :elephant Var get-pizza Data structures.
- 16. List (1 2 3 4 5) Vector [1 2 3 4 5] Map {:hello “world”} Set #{1 2 3 4 5} Data structures.
- 17. (explore-temple :machete :whip :gun) Syntax.
- 19. Given a map of args, construct a URL string. Example.
- 20. “Simplicity does not precede complexity, but follows it.” Example. Alan Perlis
- 21. Example. {:tool “whip” :garment “hat” :nationality “american” :location “jungle”} ?tool=whip&garment=hat&nationality=american&location=jungle
- 22. First attempt. (def args {:tool "whip" :garment "hat" :nationality "american" :location "jungle"}) (defn stringify [arg] (update-in arg [0] name)) (defn splice-eqal [[key-part val-part]] [key-part "=" val-part]) ( ->> args (vec) (map stringify) (map splice-equal) (interpose "&") (flatten) (apply str))
- 23. Final result. (defn format-arg "Takes a vector of two items, where the first is a keyword, which it turns into a string. It then splices in an = between the two items, and fuses them all together into a single string.” [[key-part val-part]] (str (name key-part) "=" val-part)) (defn make-string "Takes a vector of args as strings, interposes ‘&’ between them and then mashes everything in it together into a string." [args] ( ->> args (interpose “&”) (apply str))) (defn make-args "Turns a map of args into a string." [args] (make-string (map format-arg args)))
- 24. What about frontend development? Example.
- 25. Frontend development. ;; The state (defonce app-state (atom 0)) ;; Functions for modifying state (defn increase-int [] (swap! app-state inc)) (defn decrease-int [] (swap! app-state dec)) ;; The "template" for page content (defn hello-world [] [:div [:h1 (str "Current value in app-state: " @app-state)] [:button {:on-click increase-int} "Inc"] [:button {:on-click decrease-int} "Dec"]]) ;; How we mount the "template" (reagent/render-component [hello-world] (. js/document (getElementById "app"))) The rendered result
- 26. Most work is done in libraries. core.async decouples systems, adds both thread- based and in-thread asynchrony. core.spec regexes for data structures: validation (syntactically and semantically), generates automatic tests, generates documentation, generates APIs, etc. transducers higher order functions on steroids. transit type-aware data structures on the wire.
- 27. How to learn how to think. Use it.
- 28. How to learn how to think. “The value of a language that strongly enforces a paradigm is that it immerses you in that approach to solving problems. “The more it enforces the paradigm, the more you are forced to attempt solutions using that paradigm. “The more functional your language, the more training you get in approaching problems in a functional way.“ Can I do FP in my language? Eric Normand
- 29. Incentives.
- 30. Things to have a look at. Simple Made Easy. How complexity impacts business performance. https://www.infoq.com/presentations/Simple-Made-Easy Success stories. Some examples of Clojure in production. https://clojure.org/community/success_stories Clojure TV on Youtube. Tons of lectures and education. https://www.youtube.com/user/ClojureTV Clojure for the Brave and True. A gentle introduction to the language. https://www.braveclojure.com/clojure-for-the-brave-and-true/