public override Expr Nud()
{
if (Tokenizer.Current.Text == "#") // <id> # <id>
{
Tokenizer.Advance("#");
IdToken id2 = Tokenizer.GetToken() as IdToken;
if (id2 == null)
throw new ParseException("Expected constant name", id2);
return new ConExpr(this, id2);
}
if (Tokenizer.Current.Text == "(") // <id> ( <arglist> ) (method call)
{
ArrayList argList = ParseArgumentList(Tokenizer);
return new CallExpr(null, this, null, argList);
}
if (Tokenizer.Current.Text == ".") // <id> . <something>
{
Tokenizer.Advance(".");
if (Tokenizer.Current is IdToken) // <id> . <id> (method call)
{
IdToken method = Tokenizer.GetToken() as IdToken;
ArrayList argList = ParseArgumentList(Tokenizer);
return new CallExpr(this, method, null, argList);
}
else if (Tokenizer.Current is SizeToken) // <id> . BYTE|WORD|LONG
{
int size = SizeSpecifier(Tokenizer.GetToken().Text);
VariableExpr v = new VariableExpr(this, size);
if (Tokenizer.Current.Text == "[") // <id> . BYTE|WORD|LONG [ <expr> ]
{
Tokenizer.Advance("[");
ArrayList indexExprList = new ArrayList();
indexExprList.Add(ParseExpression(Tokenizer, 13));
v.IndexExprList(indexExprList);
Tokenizer.Advance("]");
}
return v;
}
}
if (Tokenizer.Current.Text == "[") // <id> [ <expr> ( , <expr> )* ]
{
Tokenizer.Advance("[");
ArrayList indexExprList = new ArrayList();
VariableExpr v = new VariableExpr(this, 0);
while (true)
{
Expr e = ParseExpression(Tokenizer, 13);
indexExprList.Add(e);
if (Tokenizer.Current.Text != ",")
break;
Tokenizer.Advance(",");
}
Tokenizer.Advance("]");
if (Tokenizer.Current.Text == ".") // <id> [ <expr> ( , <expr> )* ] . <id> (method call)
{
Tokenizer.Advance(".");
if (indexExprList.Count > 1)
{
throw new ParseException("multiple dimensions not allowed", ((Expr)indexExprList[1]).Token);
}
if (Tokenizer.Current is IdToken)
{
IdToken method = Tokenizer.GetToken() as IdToken;
ArrayList argList = ParseArgumentList(Tokenizer);
return new CallExpr(this, method, (Expr)indexExprList[0], argList);
}
else
throw new ParseException("Expected method name", Tokenizer.Current);
}
else // <id> [ <expr> ( , <expr> )* ] -- i.e., variable with at least one subscript
{
v.IndexExprList(indexExprList);
}
return v;
}
return new IdExpr(this);
}
public void Visit(VariableExpr e)
{
throw new ParseException("Variable not allowed in constant expression", e.Token);
}