static void simplify_PostProcess(ObservableCollection <IBooleanUnit> condition)
{
//remove same item in little units
//i.e. AABC+BCBD=ABC+BCD
IList <IBooleanUnit> temp = new List <IBooleanUnit>();
IList <int> toRemove = new List <int>();
int i = 0;
while (i < condition.Count)
{
if (condition[i] is BooleanVeriable)
{
if (temp.Contains(condition[i]))
{
toRemove.Add(i);
}
else
{
temp.Add(condition[i]);
}
}
else if (condition[i] == LogicalOperator.Or)
{
temp.Clear();
}
i++;
}
if (toRemove.Count > 0)
{
System.Console.WriteLine("去除最小项中的重复项");
Log("Del redundent veriables in term");
int ii = 0;
foreach (var removeI in toRemove)
{
condition.RemoveAt(removeI - ii);
if (condition[removeI - ii] == LogicalOperator.And)
{
condition.RemoveAt(removeI - ii);
}
else if (condition[removeI - ii - 1] == LogicalOperator.And)
{
condition.RemoveAt(removeI - ii - 1);
}
else
{
System.Diagnostics.Debug.Assert(false, "we should not come here!");
}
ii += 2;
}
BooleanExpressionToStringConverter cv = new BooleanExpressionToStringConverter();
System.Console.WriteLine(cv.Convert(condition, null, null, null));
Log(cv.Convert(condition, null, null, null).ToString());
}
}
//http://www.allaboutcircuits.com/vol_4/chpt_7/5.html
//http://webster.cs.ucr.edu/AoA/Windows/HTML/DigitalDesigna3.html
//http://en.wikipedia.org/wiki/Boolean_algebra
static bool simplify(ObservableCollection <IBooleanUnit> condition)
{
if (condition == null || condition.Count == 0)
{
return(true);
}
BooleanExpressionToStringConverter cv = new BooleanExpressionToStringConverter();
System.Console.WriteLine("表达式：");
Log("Expression:");
System.Console.WriteLine(cv.Convert(condition, null, null, null));
Log(cv.Convert(condition, null, null, null).ToString());
//remove meaningless parenthesis
//(ABC)(!A)=ABC!A
int leftParenthesisIndex_toRemove = -1;
int rightParennthesisIndex_toRemove = -1;
bool toRemoveAgain = true;
while (toRemoveAgain)
{
toRemoveAgain = false;
for (int i = 0; i < condition.Count; i++)
{
if (condition[i] == Parenthesis.LeftParenthesis)
{
leftParenthesisIndex_toRemove = i;
}
else if (condition[i] == LogicalOperator.Or)
{
leftParenthesisIndex_toRemove = -1;
}
else if (condition[i] == Parenthesis.RightParenthesis && leftParenthesisIndex_toRemove != -1)
{
//remove
rightParennthesisIndex_toRemove = i;
condition.RemoveAt(leftParenthesisIndex_toRemove);
condition.RemoveAt(rightParennthesisIndex_toRemove - 1);
System.Console.WriteLine("去除无意义的括号：");
Log("Del meaningless parenthesises");
System.Console.WriteLine(cv.Convert(condition, null, null, null));
Log(cv.Convert(condition, null, null, null).ToString());
toRemoveAgain = true;
break;
}
}
}
//end remove meanlingless parenthesis
//find a pair of inner parenthesis
int lastLeftParenthesisIndex = -1;
int lastRightParenthesisIndex = -1;
for (int i = 0; i < condition.Count; i++)
{
if (condition[i] == Parenthesis.LeftParenthesis)
{
lastLeftParenthesisIndex = i;
}
if (condition[i] == Parenthesis.RightParenthesis)
{
lastRightParenthesisIndex = i;
if (lastLeftParenthesisIndex == -1)
{
MessageBox.Show("左右括号不匹配");
return(false);
}
break;
}
}
if (lastLeftParenthesisIndex != -1 && lastRightParenthesisIndex == -1)
{
MessageBox.Show("左右括号不匹配");
return(false);
}
//sucess
if (lastLeftParenthesisIndex == -1 && lastRightParenthesisIndex == -1)
{
if (condition[condition.Count - 1] is LogicalOperator)
{
MessageBox.Show("最后一项为逻辑运算符，请确保输入正确");
return(false);
}
return(true);
}
//remove the parentheris
///left
if (lastLeftParenthesisIndex > 0)
{
IBooleanUnit lastLeftOutputUnit = condition[lastLeftParenthesisIndex - 1];
if (lastLeftOutputUnit == LogicalOperator.Neg)
{
NegParenthesis(condition, ref lastLeftParenthesisIndex, ref lastRightParenthesisIndex);
System.Console.WriteLine("！左乘括弧");
Log("Evaluate !(abc..) expression");
System.Console.WriteLine(cv.Convert(condition, null, null, null));
Log(cv.Convert(condition, null, null, null).ToString());
}
else if (lastLeftOutputUnit == LogicalOperator.And)
{
AndParethesis_Left(condition, ref lastLeftParenthesisIndex, ref lastRightParenthesisIndex);
System.Console.WriteLine("左乘括弧");
Log("Evaluate A(B+C...) expression");
System.Console.WriteLine(cv.Convert(condition, null, null, null));
Log(cv.Convert(condition, null, null, null).ToString());
}
}
///right
if (lastRightParenthesisIndex < condition.Count - 1)
{
IBooleanUnit nextRightOutputUnit = condition[lastRightParenthesisIndex + 1];
if (nextRightOutputUnit == LogicalOperator.And)
{
if (!AndParethesis_Right(condition, ref lastLeftParenthesisIndex, ref lastRightParenthesisIndex))
{
return(false);
}
else
{
System.Console.WriteLine("右乘括弧");
Log("Evaluate (B+C...)A expression");
System.Console.WriteLine(cv.Convert(condition, null, null, null));
Log(cv.Convert(condition, null, null, null).ToString());
}
}
}
//remove
bool toRemove = true;
if ((lastLeftParenthesisIndex > 0 && condition[lastLeftParenthesisIndex - 1] == LogicalOperator.And) ||
(lastLeftParenthesisIndex > 0 && condition[lastLeftParenthesisIndex - 1] == LogicalOperator.Neg))
{
toRemove = false;
}
if (lastRightParenthesisIndex < condition.Count - 1 && condition[lastRightParenthesisIndex - 1] == LogicalOperator.And)
{
toRemove = false;
}
if (toRemove)
{
System.Console.WriteLine("删除左右括弧");
Log("DEL left and right parenthesises");
condition.RemoveAt(lastLeftParenthesisIndex); lastRightParenthesisIndex--;
condition.RemoveAt(lastRightParenthesisIndex);
}
//re
if (simplify(condition))
{
return(true);
}
else
{
return(false);
}
}