function smd_if($atts,$thing) {
	global $thisarticle, $pretext;

	extract(lAtts(array(
		'field' => '',
		'operator' => 'eq',
		'value' => 'NULL',
		'logic' => 'and',
		'debug' => '0',
	), $atts));

	// Special field names that refer to $pretext or elsewhere - everything else is assumed to
	// exist in $thisarticle so custom fields can be used
	$allPtxt = array(
		"id" => '$pretext["id"]',
		"section" => '$pretext["s"]',
		"category" => '$pretext["c"]',
		"query" => '$pretext["q"]',
		"pg" => '$pretext["pg"]',
		"status" => '$pretext["status"]',
		"next_id" => ((isset($pretext['next_id'])) ? '$pretext["next_id"]' : ''),
		"next_title" => ((isset($pretext['next_title'])) ? '$pretext["next_title"]' : ''),
		"prev_id" => ((isset($pretext['prev_id'])) ? '$pretext["prev_id"]' : ''),
		"prev_title" => ((isset($pretext['prev_title'])) ? '$pretext["prev_title"]' : ''),
	);
	// Each entry has the operation to be eval()d later, it's "type" (test VALue or VARiable) and a list of disallowed fields
	$allOps = array(
		"eq" => array("FIELD === 'VALUE'", "VAL", ""),
		"not" => array("FIELD !== 'VALUE'", "VAL", ""),
		"gt" => array("CAST FIELD > CAST 'VALUE'", "VAL", ""),
		"ge" => array("CAST FIELD >= CAST 'VALUE'", "VAL", ""),
		"lt" => array("CAST FIELD < CAST 'VALUE'", "VAL", ""),
		"le" => array("CAST FIELD <= CAST 'VALUE'", "VAL", ""),
		"begins" => array("strpos(FIELD, 'VALUE') === 0", "VAL", ""),
		"contains" => array("strpos(FIELD, 'VALUE') !== false", "VAL", ""),
		"defined" => array("isset(FIELD)", "VAR", "parent"),
		"undefined" => array("!isset(FIELD)", "VAR", "parent"),
		"isnum" => array("is_numeric(FIELD)", "VAL", ""),
		"isempty" => array("FIELD == ''", "VAL", ""),
		"isused" => array("FIELD != ''", "VAL", ""),
	);
	$numericOps = "gt, ge, lt, le";
	$fields = do_list($field);
	$ops = do_list($operator);
	$vals = do_list($value);
	$out = array();

	for ($idx = 0; $idx < count($fields); $idx++) {
		$fld = $fields[$idx];
		$fldParts = explode(":", $fld);
		$val = $vals[$idx];
		$op = $ops[$idx];
		$opParts = explode(":", $op);
		$op = (array_key_exists($opParts[0], $allOps)) ? $opParts[0] : "eq";
		$cast = ((count($opParts) == 2) && ($opParts[1] === "NUM") && (in_list($op, $numericOps))) ? '(int)' : '';

		// Get the operator replacement code
		$type = $allOps[$op][1];
		$exclude = do_list($allOps[$op][2]);
		$op = $allOps[$op][0];

		// As long as the current operator allows this field...
		if (!in_array($fldParts[0], $exclude)) {
			// Make up the test field variable
			if (array_key_exists($fldParts[0], $allPtxt)) {
				$fld = $allPtxt[$fldParts[0]];
			} else if ($fldParts[0] == "parent") {
				$level = '';
				foreach ($fldParts as $part) {
					if ($part == "parent") {
						$theCat = $pretext['c'];
					} else if (strpos($part, "CAT") === 0) {
						$theCat = $thisarticle["category".substr($part, 3)];
					} else if (strpos($part, "LVL") === 0) {
						$level = substr($part, 3);
					}
				}

				$tree = getTreePath(doSlash($theCat), 'article');
				if ($debug) {
					dmp($tree);
				}
				$items = array();
				foreach ($tree as $leaf) {
					if ($leaf['name'] == "root" || $leaf['name'] == $theCat) {
						continue;
					} else if ($level == '' || $level == $leaf['level']) {
						$items[] = $leaf['name'];
					}
				}
				$fld = doQuote(implode(" ", $items));
			} else if ($fldParts[0] == "urlvar") {
				if (count($fldParts) == 2) {
					$fld = (gps($fldParts[1]) !== '') ? '$_GET["'.$fldParts[1].'"]' : doQuote(implode("", $fldParts));
				}
			} else if ($fldParts[0] == "svrvar") {
				if (count($fldParts) == 2) {
					$fld = (serverSet($fldParts[1]) !== '') ? '$_SERVER["'.$fldParts[1].'"]' : doQuote(implode("", $fldParts));
				}
			} else {
				$fld = '$thisarticle["'.$fldParts[0].'"]';
			}

			// Find the real value to compare against (may be another field)
			if (array_key_exists($val, $allPtxt)) {
				$val = $allPtxt[$fld];
			} else if (strpos($val, "urlvar") !== false) {
				$parts = explode(":", $val);
				if (count($parts) == 2) {
					if (isset($_GET[$parts[1]])) {
						$val = $_GET[$parts[1]];
					}
				}
			} else if (strpos($val, "svrvar") !== false) {
				$parts = explode(":", $val);
				if (count($parts) == 2) {
					if (isset($_SERVER[$parts[1]])) {
						$val = $_SERVER[$parts[1]];
					}
				}
			} else if (isset($thisarticle[$val])) {
				$val = $thisarticle[$val];
			}

			// Check the type and fix the variable if necessary
			if (($type == "VAR") && !(strpos($fld, "$") === 0)) {
				$fld = "$".preg_replace("/[^a-zA-Z0-9\_]+/", "", $fld);
			}

			// Replace the string parts...
			$cmd = str_replace("CAST", $cast, $op);
			$cmd = str_replace("FIELD", $fld, $cmd);
			$cmd = "\$out[] = (".str_replace("VALUE", (($val=='' && strpos($op, "strpos") !== false) ? ' ' : $val), $cmd).") ? 'true' : 'false';";
			if ($debug) {
				dmp($cmd);
			}
			// ... and evaluate the expression
			eval($cmd);
		}
	}
	if ($debug) {
		dmp($out);
	}
	// Check logic
	$result = true;
	if (strtolower($logic) == "and" && in_array("false", $out)) {
		$result = false;
	}
	if (strtolower($logic) == "or" && !in_array("true", $out)) {
		$result = false;
	}

	return parse(EvalElse($thing, $result));
}