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![Enum.map([1, 2, 3], fn(n) -> n * 3 end)
# => [3, 6, 9]
add = fn(x) ->
fn(y) -> x + y end
end
add_one = add.(1)
add_one.(2) # => 3
Higher order func4ons
Func/ons that accept and/or return func/ons (func/ons as data)
FP Concepts in Elixir](https://image.slidesharecdn.com/elixirandelm-190520161434/85/Elixir-and-elm-22-320.jpg)
![Example Elm code
["a", "b", "c"]
[1, 2, 3]](https://image.slidesharecdn.com/elixirandelm-190520161434/85/Elixir-and-elm-36-320.jpg)
![A simple Elm app
view : Model -> Html Msg
view model =
div []
[ button [ onClick ClickedButton ]
[ text "Click Me!" ]
, div [] [ text model ]
]
https://ellie-app.com/5xRHcKVXPVBa1](https://image.slidesharecdn.com/elixirandelm-190520161434/85/Elixir-and-elm-43-320.jpg)
Uploaded byMix & Go
Elixir and elm
The document discusses the future of web development with functional programming languages like Elixir and Elm. It provides an overview of Elixir as a functional language that runs on the Erlang VM and is good for concurrency, distribution, and fault tolerance. It also discusses Elm as a functional language for building reactive front-end applications in a way that is robust and prevents runtime exceptions. Examples of code in Elixir and Elm are also provided.
Elixir and elm
- 1. The future of web development with & CezarHălmăgean Software Development Consultant I help Ruby on Rails teams ship high-quality code faster Owner @ Mix & Go SRL mixandgo.com
- 2. A quick survey Source:Stack Overflow Developer Survey Results 2016
- 3. A quick survey Source:Stack Overflow Developer Survey Results 2016
- 4.
- 5. The problem withobject-oriented languages is they’ve got all this implicit environment that they carry around with them.You wanted a banana but what you got was a gorilla holding the banana and the entire jungle. ~ Joe Armstrong (author of Erlang)
- 6.
- 7. Functional Programming It makesconcurrency possible No deadlocks, no race condi/ons Tes4ng is easy No mocks Debugging Much easier when you don’t have global state Makes code understandable Less moving parts
- 8. Avoids shared state Makesvariable history irrelevant It's declara4ve (not impera4ve) Logic is expressed without explicitly describing the flow control Favors immutability Doesn't change history Avoids side effects A state change observable outside the called func/on Functional Programming
- 10.
- 11. What is Elixir? Func4onalprogramming language José Valim (rails core, devise, simple form) Ruby like syntax Rails like web framework (Phoenix) Dynamically typed (+ typespecs) It's an alterna/ve language for the Erlang VM Erlang VM (BEAM) Tested in produc/on for the past 30 years
- 12. What is Erlang? General-purposedevelopment plaIorm Language, VM, framework (OTP) & tools Runs in the telecom industry Created and maintained by Ericsson Easy to scale horizontally Open Telecom PlaRorm (OTP) High availability Nine nines (31.536ms / year). People can die if it goes down.
- 13. What is Erlanggood at? Concurrency Context switching between Erlang processes is cheap Distribu4on Code executes on different machines Fault tolerance It recovers from errors, processes are isolated Scalability Scaling horizontally (by adding hardware) without any code changes
- 14. Erlang VM Concurrency BEAM (runsin a single OS thread) Process Scheduler CPUCPU Process Scheduler
- 15. Web server vs.Erlang Source: Elixir in Action
- 16. Example Elixir code defhello do "result" end
- 17.
- 18. Example Elixir code fn(x)-> x * x end
- 19. Example Elixir code defmoduleExample do end
- 20. {:ok, value} ={:ok, 2} PaOern matching = the match operator Mul4 clause func4ons Func/ons with the same name, but different arguments def hello("joe"), do: "Hey Joe" def hello("jim"), do: "Hey Jim" def hello({:name, val}), do: "Hey #{val}" def hello(_), do: "Hey there!" FP Concepts in Elixir
- 21. FP Concepts inElixir inc = fn(arg) -> arg + 1 end First class func4ons Func/ons are values add(multiply(5, 3), 1) 5 |> multiply(3) |> add(1) def perform(number) do number |> multiply(3) |> add(1) end Composi4on Combine func/ons by applying a func/on to the output of another func/on
- 22. Enum.map([1, 2, 3],fn(n) -> n * 3 end) # => [3, 6, 9] add = fn(x) -> fn(y) -> x + y end end add_one = add.(1) add_one.(2) # => 3 Higher order func4ons Func/ons that accept and/or return func/ons (func/ons as data) FP Concepts in Elixir
- 23. # Pure def inc(x),do: x + 1 # Impure def dec(x), do: System.system_time - x Pure func4ons Given the same inputs, always returns the same output, and have no side-effects Referen4al transparency The defini/on can be replaced with it's value FP Concepts in Elixir
- 24. Elixir for developers Syntaxsimilar to Ruby It’s easy to get started Teaches you a new way of thinking If you're used to OOP Easy to test No mutable state, data in -> data out Code quality Compile /me checks, tes/ng, doctests
- 25. When to chooseElixir Low latency Soa real /me High reliability You really need the system to be up all the /me You want to use Erlang And you hate the syntax Highly distributed systems Systems that run on mul/ple CPUs/machines
- 26. When NOT tochoose Elixir Parallelism Not designed for parallelism, but for fault tolerance and high availability Learning curve FP, OTP, BEAM, Phoenix Speed (number crunching) C/C++ are befer at CPU intensive computa/ons Ecosystem 36.000 repos (Elixir) vs. 1.500.000 repos (Ruby) vs. 5.000.000 JS
- 27. Elixir for business Responsive Regardlessof how many clients are connected Lower maintenance/growth costs Easier to grow, less regression bugs Highly available 99,9999999% (31.536ms / year) Never crashes Errors do not bring the whole system down
- 28.
- 29. What is Elm? Func4onalprogramming language For building front-end web applica/ons No run4me excep4ons The killer feature Reac4ve by design FRP isn't opt-in, it is baked right in the language Automa4cally enforced seman4c versioning No user will ever get a breaking API change
- 30.
- 31. The Elm language Immutablevalues No history changes Type inference Helps the compiler analyze the code Strong sta4c types Finding errors fast with readable compiler messages Type annota4ons Documenta/on, simplified debugging
- 32. The Elm language PaOernmatching Makes it easy to extract data from a data structure Great debugger Inspect the history of your program Automa4c code formaWng Removes arguments about code style Pure func4ons Easy to reuse, and compose func/ons
- 33. Elm popularity Metric 03/201805/2019 Diff GitHub repos 10557 13830 31 % GitHub users 823 1074 30 % Updated in the last week 309 252 -18 % Updated in the last month 759 639 -16 % Repos with >100 stars 75 111 48 % Packages in the index 1301 1695 30 % Package authors 569 724 27 % Subscribers on r/elm 6145 7730 26 % Users on Elm Discourse 653 1672 156 %
- 34. Example Elm code 123: Int 12.3 : Float
- 35. Example Elm code "abcd": String 'abcd' : Char """ multiline string multiline string """
- 36. Example Elm code ["a","b", "c"] [1, 2, 3]
- 37. Example Elm code steve= { name = "Jobs", age = 56 } steve.name steve.age
- 38. Example Elm code typeUserStatus = Regular | Visitor
- 39. Example Elm code typealias Point = { x: Float, y: Float }
- 40. Example Elm code squaren = n^2 sum a b = a + b
- 41. Example Elm code isEven: Int -> Bool isEven n = remainderBy 2 n == 0 isOdd : Int -> Bool isOdd n = (not << isEven) n isOdd = not << isEven
- 42. A simple Elmapp type alias Model = String type Msg = ClickedButton update : Msg -> Model -> Model update msg model = case msg of ClickedButton -> "YEY!" https://ellie-app.com/5xRHcKVXPVBa1
- 43. A simple Elmapp view : Model -> Html Msg view model = div [] [ button [ onClick ClickedButton ] [ text "Click Me!" ] , div [] [ text model ] ] https://ellie-app.com/5xRHcKVXPVBa1
- 44. Programming paradigms andlanguages are tools, not religions.Try them out, gain experience, extend your toolbox, then choose the right tool for the job.
- 45. Cezar Hălmăgean mixandgo.com & The futureof web development with