begin
  var a := 2;
  var b := 3;
  var c := 4;
  var s := $'Hello {a}';
  assert(s = 'Hello 2');
  s := $'{a},{b},{c}';
  assert(s = '2,3,4');
  s := $'{a+1},{b+1},{c+1}';
  assert(s = '3,4,5');
  assert($'abc'=$'abc');
end.