public PrgState Execute(PrgState state)
{
Adt.IDictionary <string, int> symTable = state.SymTable;
IMap <ITuple <string, StreamReader> > fileTable = state.FileTable;
int fd = exp.Eval(symTable);
try
{
StreamReader sr = fileTable.LookUp(fd).Second;
string line;
line = sr.ReadLine();
int number;
if (line == null)
{
number = 0;
}
else
{
int.TryParse(line, out number);
}
symTable.Add(varName, number);
return(state);
}
catch (InvalidKeyException)
{
throw new FileDescriptorException();
}
}
public PrgState Execute(PrgState state)
{
HashSet <string> fileNames = GetFileNames(state);
if (fileNames.Contains(fileName))
{
throw new FileAlreadyOpenedException();
}
StreamReader sr = new StreamReader(fileName);
IMap <ITuple <string, StreamReader> > fileTable = state.FileTable;
ITuple <string, StreamReader> tuple = new MyTuple <string, StreamReader>(fileName, sr);
fileTable.Add(tuple);
Adt.IDictionary <string, int> symTable = state.SymTable;
symTable.Add(varFileId, fileTable.Key);
return(state);
}
public override int Eval(Adt.IDictionary <string, int> tbl)
{
switch (op)
{
case "+":
return(exp1.Eval(tbl) + exp2.Eval(tbl));
case "-":
return(exp1.Eval(tbl) - exp2.Eval(tbl));
case "*":
return(exp1.Eval(tbl) * exp2.Eval(tbl));
case "/":
return(exp1.Eval(tbl) / exp2.Eval(tbl));
default:
throw new InvalidOperatorException();
}
}