/// <summary>
/// Convert "status" enums to stateValues. Since status is a "superset"
/// we can end up with "undefineds" a lot.
/// </summary>
/// <param name="val"></param>
/// <returns></returns>
private static stateValues StatusToStateValue(status val)
{
stateValues state = stateValues.isundefined;
if (val == status.isfalse)
{
state = stateValues.isfalse;
}
else if (val == status.istrue)
{
state = stateValues.istrue;
}
return(state);
}
/// <summary>
/// We can initialize an element to 3 states:
/// 0 / 1 / x
/// </summary>
/// <param name="type">"type" of value written, invariably "value"</param>
/// <param name="state">the state of the value, 1/0/x</param>
public Element(eType type, stateValues state)
{
this.elementType = type;
switch (state)
{
case stateValues.istrue:
this.elementValue = "1";
break;
case stateValues.isfalse:
this.elementValue = "0";
break;
default:
this.elementType = eType.unknown;
this.elementValue = "x"; // undefined
break;
}
}
/// <summary>
/// handles our "single operand" operators, such as the ! operator
/// and any others we define later.
/// </summary>
/// <param name="items"></param>
/// <param name="startpos"></param>
/// <param name="endpos"></param>
/// <returns></returns>
private static status ProcessSingleOperation(Elements items, int startpos, ref int endpos)
{
for (int i = startpos; i < endpos; i++)
{
if (items[i].Operation == Element.opType.Not) // found one!
{
status nstat = Evaluate(items[i + 1], items[i]);
if (nstat != status.isfalse && nstat != status.istrue && nstat != status.isundefined)
{
return(nstat); // this is a problem`
}
try
{
items.RemoveAt(i);
items.RemoveAt(i);
}
catch (System.ArgumentOutOfRangeException ex)
{
string msg = ex.Message;
throw ex;
}
// replace the elements we stripped out with the evaluated value
stateValues state = stateValues.isundefined;
if (nstat == status.isfalse)
{
state = stateValues.isfalse;
}
else if (nstat == status.istrue)
{
state = stateValues.istrue;
}
Element e = new Element(Element.eType.value, state);
items.InsertAt(i, e);
endpos--;
}
}
return(status.success);
}
