diff --git a/lib/BooleanSearch.php b/lib/BooleanSearch.php
new file mode 100644
index 0000000..2bb9ada
--- /dev/null
+++ b/lib/BooleanSearch.php
@@ -0,0 +1,258 @@
+<?php
+
+// Token types
+define("TOKEN_STRING",       0);
+define("TOKEN_AND",          1);
+define("TOKEN_OR",           2);
+define("TOKEN_NOT",          3);
+define("TOKEN_LEFTPAREN",    4);
+define("TOKEN_RIGHTPAREN",   5);
+define("TOKEN_PLUS",         6);
+define("TOKEN_MINUS",        7);
+
+/**
+* Tokenize a search criteria string in pseudo-google format
+* e.g: this that OR (this and "the other") +this -that \+also
+*
+* @returns array of (tokentype, token) tuples.
+* e.g:  ((TOKEN_STRING, "this"),
+*        (TOKEN_STRING, "that"),
+*        (TOKEN_OR, "OR"),
+*        (TOKEN_LEFTPAREN, "("),
+*        (TOKEN_STRING, "this"),
+*        (TOKEN_AND, "and"),
+*        (TOKEN_STRING, "the other"),
+*        (TOKEN_RIGHTPAREN, ")"),
+*        (TOKEN_PLUS, "+"),
+*        (TOKEN_STRING, "this"),
+*        (TOKEN_MINUS, "-"),
+*        (TOKEN_STRING, "that"),
+*        (TOKEN_STRING, "+also"))
+*
+* Based on example code in the PHP manual on php.net
+*/
+function tokenize($criteria) {
+
+    $tokens = array(
+        TOKEN_STRING => '',
+        TOKEN_AND => 'and',
+        TOKEN_OR => 'or',         
+        TOKEN_NOT => 'not',        
+        TOKEN_LEFTPAREN => '(',  
+        TOKEN_RIGHTPAREN => ')', 
+        TOKEN_PLUS => '+',       
+        TOKEN_MINUS => '-');      
+
+    // automaton [states][chartypes] => actions
+    // states:
+    // STATE_SPACE		      0
+    // STATE_UNQUOTED	      1
+    // STATE_DOUBLEQUOTED   2
+    // STATE_ESCAPED		    3
+
+    $chart = array(
+        0   => array(' '=>'',   '"'=>'d',  '\\'=>'ue', '+'=>'uaw ', '-'=>'uaw ', '('=>'uaw ', ')'=>'uaw ', 0 =>'ua'),
+        1   => array(' '=>'w ', '"'=>'wd', '\\'=>'e',  '+'=>'waw',  '-'=>'waw',  '('=>'waw',  ')'=>'waw',  0 =>'a'),
+        2   => array(' '=>'a',  '"'=>'w ', '\\'=>'e',  '+'=>'a',    '-'=>'a',    '('=>'a',    ')'=>'a',    0 =>'a'),
+        3   => array(' '=>'ap', '"'=>'ap', '\\'=>'ap', '+'=>'ap',   '-'=>'ap',   '('=>'ap',   ')'=>'ap',   0 =>'ap'));
+
+    $state = 0;					// STATE_SPACE
+    $previous = '';     // stores current state when encountering a backslash (which changes $state to STATE_ESCAPED, but has to fall back into the previous $state afterwards)
+    $out = array();     // the return value
+    $word = '';
+    $type = '';         // type of character
+
+    for ($i=0; $i<=strlen($criteria); $i++) {
+        $char = substr($criteria, $i, 1);
+        $type = $char;
+        if (!isset($chart[0][$type])) {
+            $type = 0; //other
+            // grab all consecutive non word-ending characters
+            preg_match("/[ \+\-\(\)\"\\\]/", $criteria, $matches, PREG_OFFSET_CAPTURE, $i);
+            if ($matches) {
+                $matches = $matches[0];
+                $char = substr($criteria, $i, $matches[1]-$i); // yep, $char length can be > 1
+                $i = $matches[1] - 1;
+            }else{
+                // no more match on special characters, that must mean this is the last word!
+                // the .= below is because we *might* be in the middle of a word that just contained special chars
+                $word .= substr($criteria, $i);
+                break; // jumps out of the for() loop
+            }
+        }
+        $actions = $chart[$state][$type];
+        for($j=0; $j<strlen($actions); $j++) {
+            $act = substr($actions, $j, 1);
+            if ($act == ' ') $state = 0; //STATE_SPACE
+            if ($act == 'u') $state = 1; //STATE_UNQUOTED
+            if ($act == 'd') $state = 2; //STATE_DOUBLEQUOTED
+            if ($act == 'e') { $previous = $state; $state = 3; } //STATE_ESCAPED
+            if ($act == 'a') $word .= $char;
+            if ($act == 'p') $state = $previous;
+            if ($act == 'w') {
+                if (!empty($word)) {
+                    $tokentype = TOKEN_STRING;
+                    if ($state == 1) {
+                        //unquoted word, so look for keywords or operators
+                        $tokentype = array_search(strtolower($word), $tokens);
+                        if (!$tokentype) $tokentype = TOKEN_STRING;
+                    }
+                    $out[] = array($tokentype, $word);
+                    $word = ''; 
+                }
+            }
+        } //for j
+    } //for i
+
+    if (!empty($word)) {
+        $tokentype = TOKEN_STRING;
+        if ($state == 1) {
+            //unquoted word, so look for keywords or operators
+            $tokentype = array_search(strtolower($word), $tokens);
+            if (!$tokentype) $tokentype = TOKEN_STRING;
+        }
+        $out[] = array($tokentype, $word);
+        $word = ''; 
+    }
+    return $out;
+} //tokenize
+
+/**
+ * parse the criteria string according to a subset of the Google search syntax:
+ *
+ * example:  this too AND +this OR (these AND "the other") -notthis
+ *
+ * @return array of criterias, each criteria being an array:
+ * array (0 => operator,       ' AND ',' OR ',' AND NOT '
+ *        1 => value,          the criteria's string value
+ *        2 => wildcard flag,  TRUE if wildcard matching, FALSE for strict matching
+ *        3 => nesting)        parentheses nesting level 0..n
+ *
+ * for convenience, the operator of the first criteria is blank.
+ */
+function parsecriteria($criteria) {
+
+	$results = array();
+	$tokens = array();
+	
+	$thisresult = array('','',TRUE,0);
+	$nesting = 0;
+	//var_dump($criteria); //@@@
+	
+	//replace html quoting put there by some browsers, then tokenize
+	$tokens = tokenize(str_replace ('&quot;', '"', $criteria));
+	//var_dump($tokens); //@@@
+	
+	foreach ($tokens as $token) {
+	    switch ($token[0]) { 
+	        case TOKEN_AND:
+	            $thisresult[0] = ' AND ';
+	            $thisresult[2] = TRUE; //reset wildcard in case of bad syntax
+	            break;
+	
+	        case TOKEN_OR:
+	            $thisresult[0] = ' OR ';
+	            $thisresult[2] = TRUE; //reset  wildcard in case of bad syntax
+	            break;
+	
+	        case TOKEN_PLUS:
+	            $thisresult[2] = FALSE;
+	            break;
+	
+	        case TOKEN_NOT:
+	        case TOKEN_MINUS:
+	            $thisresult[0] .= ' NOT '; //NOT or AND NOT
+	            break;
+	
+	        case TOKEN_LEFTPAREN:
+	            $nesting += 1;
+	            $thisresult[2] = TRUE; //reset just in case of bad syntax
+	            break;
+	
+	        case TOKEN_RIGHTPAREN:
+	            $nesting -= 1;
+	            $thisresult[2] = TRUE; //reset just in case of bad syntax
+	            break;
+	
+	        default:
+	            // anything else -> output "as is"
+	            $thisresult[1] .= $token[1];
+	            $thisresult[3]  = $nesting;
+	            $results[] = $thisresult;
+	            $thisresult = array(' AND ','',TRUE,0);
+	            break;
+	    }
+	} //foreach $tokens
+	return $results;
+
+} //parsecriteria
+
+
+function assemble_query ($criteria, $searchfields) {
+	global $mysql, $username, $search;
+	$whereCriterias = parsecriteria ($criteria); 
+	//var_dump($whereCriterias); //@@@
+	
+	
+	$whereData = array();
+	$columnNumber = 0;
+	
+	$whereClause = "";
+	$nesting = 0;
+	foreach ($whereCriterias as $mycriteria) {
+	    $whereClause .= $mycriteria[0];
+	
+	    $thisnesting = $mycriteria[3];
+	    if ($thisnesting >= $nesting) {
+	        $whereClause .= str_repeat('(', $thisnesting - $nesting);
+	    } else {
+	        $whereClause .= str_repeat(')', $nesting - $thisnesting);
+	    }
+	    $nesting = $thisnesting;
+	
+	    $firstcolumn = TRUE;
+	    $whereClause .= ' (';
+	    foreach ($searchfields as $column) {
+	        if ($firstcolumn) {
+	            $firstcolumn = FALSE;
+	        } else    {
+	            $whereClause .= ' OR ';
+	        }
+	
+	        if ($mycriteria[2]) {
+	            $whereClause .= "$column LIKE " . '\'' .'%' . $mysql->escape ($mycriteria[1]) . '%' . '\'' ;
+	        } else {
+	            /* no wildcard, so match exact words using a REGEXP */
+	            $whereClause .= "$column RLIKE " . '\'' . '[[:<:]]' . $mysql->escape ($mycriteria[1]) .  '[[:>:]]' . '\'';
+	        }
+	    } //foreach $column
+	    $whereClause .= ')';
+	} //foreach $whereCriterias
+
+	$whereClause .= str_repeat(')', $nesting);
+
+	$query = sprintf ("SELECT bookmark.title,
+				bookmark.url,
+				bookmark.description,
+				UNIX_TIMESTAMP(bookmark.date) AS timestamp,
+				bookmark.childof,
+				bookmark.id,
+				bookmark.favicon,
+				bookmark.public,
+				folder.name,
+				folder.id AS fid,
+				folder.public AS fpublic
+				FROM bookmark LEFT JOIN folder ON bookmark.childof=folder.id
+
+				WHERE bookmark.user='%s'
+				AND bookmark.deleted!='1'
+				AND ( %s )
+				ORDER BY title",
+				$mysql->escape ($username),
+				$whereClause);
+
+	return $query;
+
+}
+
+?>
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