nice_lang.go

package main

import logger from log

// Function inline definition
fn hello(name string) string = "Hello {name}"

// Pattern matching
fn fib(n int) int = match n {
  case n < 0: panic("Negative values not allowed")
  case 0, 1 : n
  default   : fib(n-2) + fib(n-1)
}

// If-Then-Else as expresion
fn fib(n int) int =
  if n < 0 panic("Negative values not allowed")
  if n < 2 return n
  else     return fib(n-2) + fib(n-1)

// Function definition with block
fn add(a, b int) int = {
  a + b
}

// If-Then-Else with blocks
fn allowed(id int) bool = {
  if id > 5 {
    // complex logic
  } else {
    // more complex logic
  }
}

// Variable definition + assignment
var myVar = "With type inference" // myVar is string == true

// Constant definition of type fn(int) string a.k.a closure
val map = (data int) string {
  if data % 2 == 0 return "even"
  else             return "odd"
}

val categorize = (ls List<string>) string {
  match ls {
    case h :: nil      -> "single item list"
    case h :: t :: nil -> "multi items list"
    else               -> "empty list"
  }
}

// Type alias
type Integer int

type Greeter interface {
  fn Greet(name string) string
}

type Person class {
  Name string
  Age  int
  
  fn Greet(name string) string = "Hello {name}"
}
  
type User class : Person {
  Id string
  
  override fn Greet(name string) string = "Hello from User, Mr. {name}"
}