Expression PrimaryExpression()
{
if (Current.TokenKind == TokenKind.StringStart)
return ReadString();
else if (Current.TokenKind == TokenKind.ID)
{
Token id = Consume();
Expression exp = null;
// if ( follows ID, we have a function call
if (Current.TokenKind == TokenKind.LParen)
{
Consume(); // consume LParen
Expression[] args = ReadArguments();
Consume(TokenKind.RParen);
exp = new FCall(id.Line, id.Col, id.Data, args);
}
else // else, we just have id
exp = new Name(id.Line, id.Col, id.Data);
// while we have ".", keep chaining up field access or method call
while (Current.TokenKind == TokenKind.Dot || Current.TokenKind == TokenKind.LBracket)
{
if (Current.TokenKind == TokenKind.Dot)
{
Consume(); // consume DOT
Token field = Consume(TokenKind.ID); // consume ID after dot
// if "(" after ID, then it's a method call
if (Current.TokenKind == TokenKind.LParen)
{
Consume(); // consume "("
Expression[] args = ReadArguments();
Consume(TokenKind.RParen); // read ")"
exp = new MethodCall(field.Line, field.Col, exp, field.Data, args);
}
else
exp = new FieldAccess(field.Line, field.Col, exp, field.Data);
}
else // must be LBracket
{
// array access
Token bracket = Current;
Consume(); // consume [
Expression indexExp = TopExpression();
Consume(TokenKind.RBracket);
exp = new ArrayAccess(bracket.Line, bracket.Col, exp, indexExp);
}
}
return exp;
}
else if (Current.TokenKind == TokenKind.Integer)
{
int value = Int32.Parse(Current.Data);
IntLiteral intLiteral = new IntLiteral(Current.Line, Current.Col, value);
Consume(); // consume int
return intLiteral;
}
else if (Current.TokenKind == TokenKind.Double)
{
double value = Double.Parse(Current.Data);
DoubleLiteral dLiteral = new DoubleLiteral(Current.Line, Current.Col, value);
Consume(); // consume int
return dLiteral;
}
else if (Current.TokenKind == TokenKind.LParen)
{
Consume(); // eat (
Expression exp = TopExpression();
Consume(TokenKind.RParen); // eat )
return exp;
}
else
throw new ParseException("Invalid token in expression: " + Current.TokenKind + ". Was expecting ID or string.", Current.Line, Current.Col);
}
protected object EvalArrayAccess(ArrayAccess arrayAccess)
{
object obj = EvalExpression(arrayAccess.Exp);
object index = EvalExpression(arrayAccess.Index);
if (obj is Array)
{
Array array = (Array)obj;
if (index is Int32)
{
return array.GetValue((int)index);
}
else
throw new TemplateRuntimeException("Index of array has to be integer", arrayAccess.Line, arrayAccess.Col);
}
else
return EvalMethodCall(obj, "get_Item", new object[] { index });
}