// check if a value could satisfy part of the expression
public bool CheckKey(string attributeName, AtomValue valueToCheck)
{
if (this.SimpleMinterms.ContainsKey(attributeName))
{
AtomValue result = this.SimpleMinterms[attributeName].Calculate(new List <AttributeValue>
{
new AttributeValue(attributeName, new AtomValue()
{
Type = valueToCheck.Type,
CharLimit = valueToCheck.CharLimit,
FloatValue = valueToCheck.FloatValue,
IntegerValue = valueToCheck.IntegerValue,
})
});
return(result.BooleanValue);
}
else
{
return(true);
}
}
// get the value of this Expression
public AtomValue Calculate(List <AttributeValue> row)
{
// fetch value from symbol table (from `row`)
if (this.Operator == Operator.AtomVariable)
{
AttributeValue column = row.Find(x => x.AttributeName == this.AttributeName);
if (object.ReferenceEquals(column, null))
{
throw new System.Exception($"Attribute \"{this.AttributeName}\" does not exist in this table");
}
return(column.Value);
}
// directly return the concrete value
if (this.Operator == Operator.AtomConcreteValue)
{
return(this.ConcreteValue);
}
// fetch the values of children
AtomValue leftValue = this.LeftOperand?.Calculate(row);
AtomValue rightValue = this.RightOperand?.Calculate(row);
AtomValue result = null;
// // make sure the types of children are the same
// if (leftValue?.Type != rightValue?.Type)
// {
// throw new System.Exception("OpersimpleMinterms type not matched!");
// }
// calculate the two children into a value
switch (this.Operator)
{
case Operator.AtomVariable:
throw new System.Exception("AtomVariable is not supposed to reach this step");
case Operator.AtomConcreteValue:
throw new System.Exception("AtomConcreteValue is not supposed to reach this step");
case Operator.Plus:
result = leftValue + rightValue;
break;
case Operator.Minus:
result = leftValue - rightValue;
break;
case Operator.Multiply:
result = leftValue * rightValue;
break;
case Operator.Divide:
result = leftValue / rightValue;
break;
case Operator.Negative:
result = -leftValue;
break;
case Operator.And:
result = new AtomValue();
result.Type = AttributeTypes.Int;
result.IntegerValue = (leftValue.BooleanValue && rightValue.BooleanValue)? 1 : 0;
break;
case Operator.Or:
result = new AtomValue();
result.Type = AttributeTypes.Int;
result.IntegerValue = (leftValue.BooleanValue || rightValue.BooleanValue)? 1 : 0;
break;
case Operator.Xor:
result = new AtomValue();
result.Type = AttributeTypes.Int;
result.IntegerValue = (leftValue.BooleanValue != rightValue.BooleanValue)? 1 : 0;
break;
case Operator.Not:
result = !leftValue;
break;
case Operator.LessThan:
result = leftValue < rightValue;
break;
case Operator.MoreThan:
result = leftValue > rightValue;
break;
case Operator.Equal:
result = leftValue == rightValue;
break;
case Operator.NotEqual:
result = leftValue != rightValue;
break;
case Operator.LessThanOrEqualTo:
result = leftValue <= rightValue;
break;
case Operator.MoreThanOrEqualTo:
result = leftValue >= rightValue;
break;
}
return(result);
}