ProgramState IStmt.execute(ProgramState programState)
{
FileTable fileTable = programState.getFileTable();
SymTable <string, int> symTable = programState.getSymTable();
bool found = false;
foreach (Tuple <string, TextReader> t in fileTable.Values)
{
if (t.Item1.Equals(fileName))
{
found = true;
break;
}
}
if (found)
{
throw new Exception("File already open!\n");
}
if (symTable.ContainsKey(var_file_id))
{
throw new Exception("File id already exists!\n");
}
TextReader textReader = File.OpenText(fileName);
int id = fileTable.Add(new Tuple <string, TextReader>(fileName, textReader));
symTable.Add(var_file_id, id);
return(null);
}
ProgramState IStmt.execute(ProgramState programState)
{
SymTable <string, int> symTable = programState.getSymTable();
if (symTable.ContainsKey(varName))
{
symTable[varName] = exp.evaluate(symTable);
}
else
{
symTable.Add(varName, exp.evaluate(symTable));
}
return(null);
}
ProgramState IStmt.execute(ProgramState programState)
{
FileTable fileTable = programState.getFileTable();
SymTable <string, int> symTable = programState.getSymTable();
int id = exp_file_id.evaluate(symTable);
if (!fileTable.ContainsKey(id))
{
throw new Exception("Invalid text reader id!\n");
}
TextReader textReader = fileTable[id].Item2;
string line = textReader.ReadLine();
int value;
if (line == null)
{
value = 0;
}
else
{
value = int.Parse(line);
}
if (symTable.ContainsKey(varName))
{
symTable[varName] = value;
}
else
{
symTable.Add(varName, value);
}
return(null);
}
