Task

Determine whether a given year is a leap year in the Gregorian calendar.



See also

 Leap year (wiki)


let str => import 'strings';
 
let multiple of n => == (% n of) 0;
 
let leap year => str.format '{} is{} a leap year.' year (switch year {
  multiple 400 => '';
  multiple 100 => ' not';
  multiple 4 => '';
  default => ' not';
}) -- io.writeln io.stdout;