private static IBooleanExpression BuildTree(List <BooleanExpressionToken> tokens)
{
BooleanExpressionGroup defaultGroup = new BooleanExpressionGroup();
bool not = false;
for (int i = 0; i < tokens.Count; i++)
{
var token = tokens[i];
if (token.Type == BooleanExpressionTokenType.GroupClose ||
(defaultGroup.Operands.Count == 0 && (token.Type == BooleanExpressionTokenType.And || token.Type == BooleanExpressionTokenType.Or)) ||
(i == tokens.Count - 1 && (token.Type == BooleanExpressionTokenType.And || token.Type == BooleanExpressionTokenType.Or)))
{
throw new ArgumentException("Unexpected token '" + token.Value + "'");
}
if (token.Type == BooleanExpressionTokenType.GroupOpen)
{
int numOpen = 1;
List <BooleanExpressionToken> groupedExpression = new List <BooleanExpressionToken>();
for (int j = i + 1; j < tokens.Count; j++)
{
var innerToken = tokens[j];
if (innerToken.Type == BooleanExpressionTokenType.GroupClose && numOpen == 1)
{
numOpen = 0;
i = j;
break;
}
else if (innerToken.Type == BooleanExpressionTokenType.GroupClose)
{
numOpen--;
}
else if (innerToken.Type == BooleanExpressionTokenType.GroupOpen)
{
numOpen++;
}
groupedExpression.Add(innerToken);
}
if (numOpen > 0)
{
throw new ArgumentException("You are missing at least 1 closing parenthesis");
}
if (groupedExpression.Count == 0)
{
throw new ArgumentException("You have an empty set of parenthesis");
}
var group = BuildTree(groupedExpression);
group.Not = not;
defaultGroup.Operands.Add(group);
not = false;
}
else if (token.Type == BooleanExpressionTokenType.Variable)
{
if (defaultGroup.Operands.Count != defaultGroup.Operators.Count)
{
throw new ArgumentException("Expected an operator, got variable: " + token.Value);
}
defaultGroup.Operands.Add(new BooleanVariable()
{
VariableName = token.Value, Not = not
});
not = false;
}
else if (token.Type == BooleanExpressionTokenType.And || token.Type == BooleanExpressionTokenType.Or)
{
if (not)
{
throw new ArgumentException("You cannot have an operator '&' or '|' after a '!'");
}
if (defaultGroup.Operators.Count >= defaultGroup.Operands.Count)
{
throw new ArgumentException("You cannot have two consecutive operators '&&' or '||', use '&' or '|'");
}
defaultGroup.Operators.Add((BooleanOperator)token.Type);
}
else if (token.Type == BooleanExpressionTokenType.Not)
{
if (not)
{
throw new ArgumentException("You cannot have two consecutive '!' operators");
}
else
{
not = true;
}
}
else
{
throw new ArgumentException("Unexpected token '" + token.Value + "'");
}
}
if (not == true)
{
throw new ArgumentException("Unexpected token '!' at end of expression");
}
if (defaultGroup.Operands.Count == 1)
{
return(defaultGroup.Operands[0]);
}
else
{
return(defaultGroup);
}
}
private static IBooleanExpression BuildTree(List<BooleanExpressionToken> tokens)
{
BooleanExpressionGroup defaultGroup = new BooleanExpressionGroup();
bool not = false;
for (int i = 0; i < tokens.Count; i++)
{
var token = tokens[i];
if (token.Type == BooleanExpressionTokenType.GroupClose ||
(defaultGroup.Operands.Count == 0 && (token.Type == BooleanExpressionTokenType.And || token.Type == BooleanExpressionTokenType.Or)) ||
(i == tokens.Count - 1 && (token.Type == BooleanExpressionTokenType.And || token.Type == BooleanExpressionTokenType.Or)))
{
throw new ArgumentException("Unexpected token '" + token.Value + "'");
}
if (token.Type == BooleanExpressionTokenType.GroupOpen)
{
int numOpen = 1;
List<BooleanExpressionToken> groupedExpression = new List<BooleanExpressionToken>();
for (int j = i + 1; j < tokens.Count; j++)
{
var innerToken = tokens[j];
if (innerToken.Type == BooleanExpressionTokenType.GroupClose && numOpen == 1)
{
numOpen = 0;
i = j;
break;
}
else if (innerToken.Type == BooleanExpressionTokenType.GroupClose)
{
numOpen--;
}
else if (innerToken.Type == BooleanExpressionTokenType.GroupOpen)
{
numOpen++;
}
groupedExpression.Add(innerToken);
}
if (numOpen > 0)
{
throw new ArgumentException("You are missing at least 1 closing parenthesis");
}
if (groupedExpression.Count == 0)
{
throw new ArgumentException("You have an empty set of parenthesis");
}
var group = BuildTree(groupedExpression);
group.Not = not;
defaultGroup.Operands.Add(group);
not = false;
}
else if (token.Type == BooleanExpressionTokenType.Variable)
{
if(defaultGroup.Operands.Count != defaultGroup.Operators.Count)
{
throw new ArgumentException("Expected an operator, got variable: "+token.Value);
}
defaultGroup.Operands.Add(new BooleanVariable() { VariableName = token.Value, Not = not });
not = false;
}
else if (token.Type == BooleanExpressionTokenType.And || token.Type == BooleanExpressionTokenType.Or)
{
if(not)
{
throw new ArgumentException("You cannot have an operator '&' or '|' after a '!'");
}
if (defaultGroup.Operators.Count >= defaultGroup.Operands.Count)
{
throw new ArgumentException("You cannot have two consecutive operators '&&' or '||', use '&' or '|'");
}
defaultGroup.Operators.Add((BooleanOperator)token.Type);
}
else if(token.Type == BooleanExpressionTokenType.Not)
{
if (not)
{
throw new ArgumentException("You cannot have two consecutive '!' operators");
}
else
{
not = true;
}
}
else
{
throw new ArgumentException("Unexpected token '" + token.Value + "'");
}
}
if(not == true)
{
throw new ArgumentException("Unexpected token '!' at end of expression");
}
if (defaultGroup.Operands.Count == 1)
{
return defaultGroup.Operands[0];
}
else
{
return defaultGroup;
}
}