public Types.Object Evaluate(Executer exec)
{
//when an operator has been applied to two terms, other operators that involve
//any of those terms must use the result of that operation.
//So, keep a list of pointers that point to the resulting terms.
Hashtable htTermPointers = new Hashtable();
for (int i = 0; i < this.m_aChunks.Count; i++)
{
ArrayList a = new ArrayList();
a.Add(i);
htTermPointers.Add(i, a);
}
if (this.m_slCalcOrder == null) //don't why this should happen, though...
{
this.ArrangeOpsInExecutionOrder();
}
//ArrayList aChunksCopy = new ArrayList();
ArrayList aChunksCopy = (ArrayList)this.m_aChunks.Clone();
Term t1 = null;
Term tNew = null;
for (int i = 0; i < this.m_slCalcOrder.Count; i++)
{
OperatorAndTerms opt = (OperatorAndTerms)this.m_slCalcOrder.GetByIndex(i);
ArrayList aTerm1Ptr = (ArrayList)htTermPointers[opt.Term1Index];
ArrayList aTerm2Ptr = null;
t1 = (Term)aChunksCopy[(int)aTerm1Ptr[0]]; //this.m_aChunks
Term t2 = null;
if (opt.Term2Index > 0)
{
aTerm2Ptr = (ArrayList)htTermPointers[opt.Term2Index];
t2 = (Term)aChunksCopy[(int)aTerm2Ptr[0]]; //this.m_aChunks
}
//now we've got the term(s). Perform the operation
tNew = t1.PerformOperation(exec, opt.Op, t2);
aChunksCopy[(int)aTerm1Ptr[0]] = tNew;
//if there's a second term, change the pointer to it to the first term instead
//so that successive operations use the result of this operation instead of the inital value
if (t2 != null)
{
//aTerm2Ptr = (ArrayList)htTermPointers[opt.Term2Index];
//aTerm2Ptr[0] = opt.Term1Index;
//htTermPointers[opt.Term1Index] = aTerm2Ptr;
htTermPointers[opt.Term2Index] = aTerm1Ptr;
}
}
//NOPE - no restoring, we've still got the originals (after rewrite):
//Always restore directly after execution, making it ready for next execution:
Types.Object o = tNew.Value; // t1.Value;
//this.Restore();
return(o);
}
