public int Evaluate(SymbolTableInterface <string, int> symbolTable)
{
int leftResult = leftExpression.Evaluate(symbolTable);
int rightResult = rightExpression.Evaluate(symbolTable);
switch (oper)
{
case '+': return(leftResult + rightResult);
case '-': return(leftResult - rightResult);
case '*': return(leftResult * rightResult);
case '/':
if (rightResult != 0)
{
return(leftResult / rightResult);
}
else
{
throw new DivisionByZeroException();
}
default:
throw new UnknownOperationException(oper);
}
}
private Statement statement; // as opposed to the java version, i have added an initial state here
// so there is no need for a manual push of the statement to the stack
public ProgramState(
ExecutionStackInterface <Statement> execStack,
SymbolTableInterface <string, int> symTable,
OutputListInterface <int> outList,
FileTableInterface <int, FileDescriptor> fTable,
Statement initialStatement
)
{
executionStack = execStack;
symbolTable = symTable;
outputList = outList;
fileTable = fTable;
statement = initialStatement;
execStack.push(initialStatement); // push the initial statement onto the stack
}
public void LogProgramState()
{
using (StreamWriter logFile = new StreamWriter(File.Open(fileName, FileMode.Append)))
{
ProgramState programState = Current;
ExecutionStackInterface <Statement> executionStack = programState.ExecutionStack;
SymbolTableInterface <string, int> symbolTable = programState.SymbolTable;
OutputListInterface <int> cout = programState.OutputList;
FileTableInterface <int, FileDescriptor> fileTable = programState.FileTable;
logFile.WriteLine("ExecStack:");
foreach (Statement stm in executionStack.Content)
{
logFile.WriteLine(stm);
}
logFile.WriteLine("SymTable:");
foreach (KeyValuePair <string, int> entry in symbolTable.Content)
{
logFile.WriteLine(entry.Key + " -> " + entry.Value);
}
logFile.WriteLine("Output:");
foreach (int k in cout.Content)
{
logFile.WriteLine(k);
}
logFile.WriteLine("FileTable:");
foreach (KeyValuePair <int, FileDescriptor> entry in fileTable.Content)
{
logFile.WriteLine(entry.Key + " -> " + entry.Value);
}
logFile.WriteLine();
}
}
public int Evaluate(SymbolTableInterface <string, int> symbolTable)
{
return(value);
}
public int Evaluate(SymbolTableInterface <string, int> symbolTable)
{
return(symbolTable[variableName]);
}
