public Exp power()
{
var e = atom();
if (e == null)
return null;
while (Peek(trailer_first))
{
e = trailer(e);
}
if (PeekAndDiscard(TokenType.OP_STARSTAR))
{
var r = factor();
if (r == null)
Unexpected();
e = new BinExp(Op.Exp, e, r, filename, e.Start, r.End);
}
return e;
}
//atom: ('(' [yield_expr|testlist_comp] ')' |