public Argument(Exp name, Exp defval, string filename, int start, int end) : base(filename, start, end)
{
this.name = name;
this.defval = defval;
}
public KeywordArgument(Exp t, string filename, int start, int end)
: base(t, filename, start, end)
{
}
public Lambda(List <VarArg> args, Exp body, string filename, int start, int end) : base(filename, start, end)
{
this.Body = body;
this.args = args;
}