public Exp testlist()
{
var exprs = new List<Exp>();
for (; ; )
{
exprs.Add(test());
if (!PeekAndDiscard(TokenType.COMMA))
break;
if (Peek(TokenType.COLON, TokenType.NEWLINE))
break;
}
return exprs.Count != 1 ? new ExpList(exprs, filename, exprs[0].Start, exprs.Last().End) : exprs[0];
}