title: Need guidance towards evaluative boolean logic tree
body: <p>I can't seem to find a pointer in the right direction, I am not even sure what the terms are that I should be researching but countless hours of googling seem to be spinning me in circles, so hopefully the collective hive of intelligence of Stack Overflow can help.</p>
  
  <p>The problem is this, I need a way to filter data in what I can only call a compound logic tree.    Currently the system implements a simple AND filtering system.  For example, lets say we have a dataset of people.   You add a bunch of filters such that show all the people where (Sex = Female) AND (Age > 23) AND (Age &lt; 30) AND ( Status = Single).   Easy enough, iterate through each item, add to a valid items collection only if every condition is true. </p>
  
  <p>The problem I'm encountering is how do I handle the user being able to build complex queries involved and's and or's?  I'm thinking of something like a tree where each node represents and expression evaluating its children to true or false.   A simplistic example would be - filter down to ((Sex == Male AND Age == 25) OR (Sex == Female AND Status == Single)) AND IQ > 120.   Sorry I can't think of a better example at the moment.  But how would you go about representing this type of expression tree, and evaluating the items in a collection against these filters.     What are some references that would help?  Hell, what are some damn Google searching that might lead into a positive direction?!</p>
  
  <p>Thanks to anyone that can provide any help.</p>
  
  <p>Here is an example of a compound query in tree form using a dataset of people</p>
  
  <ul>
  <li>Query - Show me all people where sex is male and eyes are green or sex is female, eyes are blue, or status is single.
  In Paren form (Sex==Male &amp;&amp; Eyes == Green) || ( Sex == Female &amp;&amp; ( Eyes == Blue || Status == Single))</li>
  </ul>
  
  <p>So In tree form im Thinking</p>
  
  <pre><code>o-Root Node
    - And - Sex = Male
       - And - Eyes = Blue
    - Or - Sex = Female
       - And Eyes = Blue
       - Or Status = Single
  </code></pre>
  
  <p>I believe the solution is to represent each node such in a data structure like</p>
  
  <pre><code>Node
  {
     OpType - AND or OR
     ExpressionField - The field to evaluate
     ExpressionOp -   =, !=, &gt;, &gt;=, &lt;, &lt;=
     ExpressionValue - the value to compare the field's value against
  
     Function Evaluate() - returns a bool
  }
  </code></pre>
  
  <p>So for a given node, evaluate the chilren, if you are an AND node, then return true if your expression results in true and  all your AND children evaluate to true or any OR child evaluates to true and recurse up.</p>
  
  <p>Seems to satisfy every conceptual condition I can throw at it, but we will since once I implement it.  I will post the real code up later when its working and pictures to help describe this problem better for others.</p>