object EvalAttribute(AttributeExpression expr, EvalOption option)
{
var value = Eval(expr.Value, option);
if (value is Attribute)
{
value = (value as Attribute).Value;
}
var table = value as SymbolTable;
if (table == null)
{
throw new UnknownValueException(expr.Attribute, expr.Line);
}
if (!table.Tables.ContainsKey(expr.Attribute))
{
throw new UnknownValueException(expr.Attribute, expr.Line);
}
return(table.Tables[expr.Attribute]);
}
Expression Group()
{
var token = Peek();
Expression value = null;
if (token != null)
{
if (token.Type == TokenType.LeftParentheses)
{
Next();
var center = Expr();
var right = Peek();
if (right != null && right.Type == TokenType.RightParentheses)
{
Next();
value = center;
}
else
{
if (token == null)
{
throw new InvalidEOFException(tokens.LastOrDefault().Line);
}
throw new CompileException(string.Format("Invalid token {0}", token), token.Line);
}
}
else if (token.Type == TokenType.Operator && ((string)token.Value == "+" || (string)token.Value == "-"))
{
Next();
var rhs = Group();
var ret = new UnaryOpExpression();
ret.Line = token.Line;
ret.Expr = rhs;
ret.Operator = (string)token.Value;
value = ret;
}
else if (token.Type == TokenType.Label)
{
var ret = Value();
ret.Line = token.Line;
value = ret;
}
else if (token.Type == TokenType.Digit)
{
Next();
var ret = new NumberExpression((float)token.Value);
ret.Line = token.Line;
value = ret;
}
else
{
throw new InvalidTokenException(token.ToString(), token.Line);
}
}
else
{
throw new InvalidEOFException(tokens.LastOrDefault().Line);
}
while (true)
{
var dotToken = Peek();
if (dotToken != null && dotToken.Type == TokenType.Dot)
{
var next = Next();
if (next == null)
{
throw new InvalidEOFException(tokens.LastOrDefault().Line);
}
else if (next.Type != TokenType.Label)
{
throw new InvalidTokenException(token.ToString(), token.Line);
}
var v_ = new AttributeExpression();
v_.Value = value;
v_.Attribute = (string)next.Value;
v_.Line = next.Line;
value = v_;
Next();
}
else
{
break;
}
}
return(value);
}