GleamGleam

import gleam/io
import gleam/list
import gleam/result

// 함수 정의
pub fn greet(name: String) -> String {
  "Hello, " <> name <> "!"
}

// 커스텀 타입 (Algebraic Data Type)
pub type Shape {
  Circle(radius: Float)
  Rectangle(width: Float, height: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14159 *. r *. r
    Rectangle(w, h) -> w *. h
  }
}

// 파이프라인 연산자
pub fn process(numbers: List(Int)) -> Int {
  numbers
  |> list.filter(fn(n) { n > 0 })
  |> list.map(fn(n) { n * n })
  |> list.fold(0, fn(acc, n) { acc + n })
}

import gleam/int
import gleam/result

pub fn safe_divide(a: Int, b: Int) -> Result(Int, String) {
  case b {
    0 -> Error("Division by zero")
    _ -> Ok(a / b)
  }
}

// use 구문: 모나딕 체이닝
pub fn compute(a: String, b: String) -> Result(Int, String) {
  use n1 <- result.try(int.parse(a))
  use n2 <- result.try(int.parse(b))
  safe_divide(n1, n2)
}

import gleam/otp/actor
import gleam/erlang/process

// Actor 모델 (Erlang 기반)
pub fn start_counter() {
  let assert Ok(subject) = actor.start(0, fn(msg, state) {
    case msg {
      Increment -> actor.continue(state + 1)
      Get(reply) -> {
        process.send(reply, state)
        actor.continue(state)
      }
    }
  })
  subject
}