my $vb = <<'__EOI__';
let a = test
let b = test                      ' Comment1
let c = """this is a ""test"""""  ' Comment2
let d = """this is a ""test"""""
__EOI__

foreach (split(/\n/, $vb)) {
  if (/^(?:[^"]|"(?:[^"]|"")*")*('.*)/) {
    print("$1\n");
  } else {
    print("No Comment.\n");
  }
}

__END__

Outputs
-------
No Comment.
' Comment1
' Comment2
No Comment.