fgalassi

% The beauty of the right programming paradigm.
% Conway's Game of life in 4 lines of Octave code.
 
function new = life(board)
  neighbours = conv2(board, [1 1 1; 1 0 1; 1 1 1], 'same')
  new = neighbours == 3 | (neighbours == 2 & board)
end

% Create a 100x100 board and run the game in a GUI

fgalassi

def square_root(x, guess)
  puts "guessing: #{guess}"
  if guess * guess == x
    guess
  else
    new_guess = (guess + x / guess) / 2
    square_root(x, new_guess)
  end
end

fgalassi

let map = (func, [head, ...tail]) => head === undefined ? [] : [func(head), ...map(func, tail)]
map(n => n + 1, [1, 2, 3])
// [2, 3, 4]

fgalassi

/**
 * The `navigate` function takes a `Path` string that
 * can contain parameter names using the `users/:username`
 * syntax. Type it so that the `params` object provided
 * as the second argument always contains a key for each variable
 * in the `Path`.
 */
namespace parseUrlParams {
  declare function navigate<U extends string>(
    path: U,

fgalassi

// This is tricky because you cannot do Str extends `${infer Before}${UnionOfSep}${infer After}` ...
type Split<Str, UnionOfSep extends string, CurrentWord extends string = "", Output extends string[] = []> =
  Str extends `${infer First}${infer Rest}`
    ? First extends UnionOfSep
      ? Split<Rest, UnionOfSep, "", [...Output, CurrentWord]>
      : Split<Rest, UnionOfSep, `${CurrentWord}${First}`, Output>
    : [...Output, CurrentWord];