//************************************************************
// static helpers to generate a Term
//************************************************************
// try to extract the next term from the string
// put the term on the stack
protected static CTerm_Base GetNextTerm(ref string Term,
Stack <CTerm_Base> Stack,
MMC.Calc.CEnvironment Env,
TPriority Prio)
{
CTerm_Base Result = null;
int Stack_Count = Stack.Count;
while (!String.IsNullOrEmpty(Term) || Result != null)
{
// if we didn't find a term yet
if (Result == null)
{
// find next operation
Result = Env.FindOp(ref Term);
// if we didn't find anything ...
if (Result == null)
{
break;
}
}
// This term ends if prio is less or equal, i.e. 2-3+2 = (2-3)+2
if (Result.Priotity <= Prio)
{
break;
}
// Let the Operation get their operands from stack or string
CTerm_Base Next = Result.Compile(ref Term, Stack, Env);
// and try to reduce the term as much as possible
TTermType Type = Result.Type;
Result = Result.Replace(Env);
// check if we have to combine this Term with the TopOfStack
// but only if the second term is not a number
// e.g. "2sqrt2" = "2*sqrt2"
if ((Type != TTermType.Number) && (Type != TTermType.Seperator) &&
(Stack.Count == Stack_Count + 1))
{
Result = Env.Combine(Stack.Pop(), Result);
Result = Result.Replace(Env);
}
// put the Operation onto the stack
Stack.Push(Result);
// and proceed with the next term (or null if none)
Result = Next;
}
return(Result);
}
//------------------------------------------------------------
// construct this object with a function or variable name
// e.g. "+" or "sin" or "pi"
public CTerm_Base(string Name, TPriority Priority, TTermType TermType)
{
_Name = Name;
_Priority = Priority;
_TermType = TermType;
}
