Hypothetical funclang

fib.lang

use <filter> as only
use <func> as F
use [Input] of <io>

fn fib(n) {
  ret F.decide({
    n <= 1 : () => n
  }).else(() => F.sum([
    fib(n - 1),
    fib(n - 2)
  ]));
}

fn main() {
  ret new Input()
    .filter(only.int)
    .once(n => {
      print('The %nth Fibonacci number is %{fib(n)}.')
    });
}

fizz_buzz.lang

use <func> as F

main() =>
  F.for([1..100])
    .map(n => F.decide({
      n % 3 && n % 5 : () => 'FizzBuzz',
      n % 3 : 'Fizz',
      n % 5 : 'Buzz'
    }).else(() => n)
    .all(print)

regex.func.lang

use <func> as F
use <regex>

main() =>
   F.src('I have 69 cats, drive 3 cars and own 12 houses.')
    .morph(rgx('[0-9]+', ['g']))
    .morph(match => match[0])
    .morph(group => 'You have %group cat(s)???')
    .pass(print);

regex.lang

use <regex>

main() {
  let matcher = rgx('[0-9]+', ['g']);
  let match = matcher('I have 69 cats, drive 3 cars and own 12 houses.');
  print('You have %{match[0]} cat(s)???');
}

task.func.lang

use <func> as F
use <task>

main() {
  let tasks = [
    new Task.value(1),
    new Task.immediate(() => 2),
    new Task(() => 3)
  ];
  
  ret F.streams(F.map(tasks, task => task.stream)).once(print);
}

task.lang

use <task>

main() {
  let task = new Task.value(1337);
  ret task.stream.once(n => {
    print('Value from task: %n');
  });
}