public static object SliceNotationVariable(Expr callee, Token token, Interpreter interpreter, object first, object second, object third)
{
//bounds checking
if (!(first is double) || ((double)first != double.NegativeInfinity && (double)first < 0) || ((double)first != double.NegativeInfinity && (double)first >= ((string)interpreter.LookupVariable(callee)).Length))
{
throw new ErrorHandler.RuntimeError(token, "First index must be a number and between 0 and String.Length(string) -1 (inclusive)");
}
if (second != null)
{
if (!(second is double) || ((double)second != double.PositiveInfinity && (double)second < 0) || ((double)second != double.PositiveInfinity && (double)second >= ((string)interpreter.LookupVariable(callee)).Length))
{
throw new ErrorHandler.RuntimeError(token, "Second index must be a number and between 0 and String.Length(string) -1 (inclusive)");
}
}
if (second == null)
{
//access this character only
return(((string)interpreter.LookupVariable(callee))[(int)(double)first]);
}
//default values for slice notation (begin and end are inclusive)
int begin = (double)first == double.NegativeInfinity ? 0 : (int)(double)first;
int end = (double)second == double.PositiveInfinity ? ((string)interpreter.LookupVariable(callee)).Length - 1 : (int)(double)second;
int step = third == null ? 1 : (int)(double)third;
//check for infinite loops
if (step == 0)
{
throw new ErrorHandler.RuntimeError(token, "Can't have a string step of 0");
}
//build the new string
string newString = "";
for (int index = step > 0 ? begin : end; index >= begin && index <= end; index += step)
{
newString += ((string)interpreter.LookupVariable(callee))[index];
}
return(new StringVariableAssignableIndex(callee, newString, interpreter, begin, end, token, third));
}
public static object VariableProperty(Variable expr, Interpreter interpreter, Token name, string lexeme)
{
string str = (string)interpreter.LookupVariable(expr);
switch (lexeme)
{
case "Length": return(new Length(str));
case "ToLower": return(new ToLower(str));
case "ToUpper": return(new ToUpper(str));
case "Replace": return(new Replace(str));
case "Trim": return(new Trim(str));
case "IndexOf": return(new IndexOf(str));
case "LastIndexOf": return(new LastIndexOf(str));
default:
throw new ErrorHandler.RuntimeError(name, "Unknown property '" + lexeme + "'");
}
}
