public ProgramState Exec(ProgramState state)
{
if (exp.Eval(state) > 0)
{
return(thenS.Exec(state));
}
if (elseS == null)
{
return(null);
}
return(elseS.Exec(state));
}
public ToyProgram OneStep()
{
if (this.Completed())
{
throw new ProgramCompletedException("All steps executed");
}
IStatement currentStatement = State.ExeStack.Pop();
ProgramState newState = currentStatement.Exec(State);
if (newState != null)
{
return(new ToyProgram(newState));
}
return(null);
}