diff --git a/RevPHPNodeVisitor.php b/RevPHPNodeVisitor.php
index 858976c..04c9839 100644
--- a/RevPHPNodeVisitor.php
+++ b/RevPHPNodeVisitor.php
@@ -171,6 +171,12 @@ public function findValue(PhpParser\Node $node, &$value) {
 			} else {
 			}
 		} else
+		if ($node instanceof PhpParser\Node\Expr\BinaryOp\BitwiseXor) {
+			if ($this->xorStrings($node, $value)) {
+				$found_value = TRUE;
+			} else {
+			}
+		} else
 		if ($node instanceof PhpParser\Node\Expr\Variable) {
 			$variable_value = null;
 			if ($node->name instanceof PhpParser\Node)
@@ -276,6 +282,10 @@ public function findName(PhpParser\Node $node, &$varname) {
 			if ($this->concatStrings($node, $varname))
 				$found_string = TRUE;
 		} else
+		if ($node instanceof PhpParser\Node\Expr\BinaryOp\BitwiseXor) {
+			if ($this->xorStrings($node, $varname))
+				$found_string = TRUE;
+		} else
 		if ($node instanceof PhpParser\Node\Scalar\String_) {
 			$varname = $node->value; # XXX - ???
 			$found_string = TRUE;
@@ -317,7 +327,7 @@ public function findName(PhpParser\Node $node, &$varname) {
 				$varname = $node->name;
 				$found_string = TRUE;
 			} else {
-				debug_print_backtrace();
+				ob_start(); debug_print_backtrace(); fwrite(STDERR, rtrim(ob_get_clean() ?: "failed to dump backtrace") . PHP_EOL);
 			}
 		} else
 		if ($node instanceof PhpParser\Node\Expr\List_) {
@@ -334,7 +344,7 @@ public function findName(PhpParser\Node $node, &$varname) {
 				# Something dreadfully wrong. This is pretty much the
 				# very last thing it could be.
 				fwrite(STDERR, "Problem in findName(), no name, line {$node->getLine()}: ".print_r($node, TRUE)."\n");
-				debug_print_backtrace();
+				ob_start(); debug_print_backtrace(); fwrite(STDERR, rtrim(ob_get_clean() ?: "failed to dump backtrace") . PHP_EOL);
 			}
 		}
 		#fwrite(STDERR, "leave findName, {$node->getType()}, name: \"$varname\"\n");
@@ -393,6 +403,26 @@ public function concatStrings(PhpParser\Node\Expr\BinaryOp\Concat $concat, &$con
 		return $found_string;
 	}
 
+	public function xorStrings(PhpParser\Node\Expr\BinaryOp\BitwiseXor $xorstring, &$xoredstring) {
+		$found_string = FALSE;
+		if ($this->findValue($xorstring->left, $leftstring)
+			&& $this->findValue($xorstring->right, $rightstring)) {
+			$xoredstring = $leftstring ^ $rightstring;
+			$found_string = TRUE;
+		} else {
+			# Replace left or right nodes with statically-determinable values, if possible
+			if ($this->findValue($xorstring->left, $leftvalue)) {
+				if (is_string($leftvalue))
+					$xorstring->left = $this->newNodeAsType($leftvalue, false);
+			}
+			if ($this->findValue($xorstring->right, $rightvalue)) {
+				if (is_string($rightvalue))
+					$xorstring->right = $this->newNodeAsType($rightvalue, false);
+			}
+		}
+		return $found_string;
+	}
+
 	public function enterNode(PhpParser\Node $node) {
 		if ($node instanceof PhpParser\Node\Stmt\Function_) {
 			$this->symtbl->pushScope();
@@ -826,6 +856,31 @@ public function leaveNode(PhpParser\Node $node) {
 					$node->left = $this->newNodeAsType($leftvalue, false);
 			}
 		} else
+		if ($node instanceof PhpParser\Node\Expr\BinaryOp\BitwiseXor) {
+			# Roll up any substrings. This can be computationally inefficient.
+			$left_is_string = false;
+			if ($this->findValue($node->left, $leftvalue)) {
+				if (is_string($leftvalue))
+					$left_is_string = true;
+			}
+			if ($this->findValue($node->right, $rightvalue)) {
+				if (is_string($rightvalue)) {
+					if ($node->left instanceof PhpParser\Node\Expr\BinaryOp\BitwiseXor) {
+						if ($this->findValue($node->left->right, $othervalue)) {
+							if (is_string($othervalue)) {
+								$node->right = $this->newNodeAsType($othervalue ^ $rightvalue);
+								$node->left  = $node->left->left;
+							}
+						}
+					} else {
+						$node->right = $this->newNodeAsType($rightvalue, false);
+					}
+				}
+			} else {
+				if ($left_is_string)
+					$node->left = $this->newNodeAsType($leftvalue, false);
+			}
+		} else
 		if ($node instanceof PhpParser\Node\Stmt\Function_) {
 			$this->substituteFunctionName($node);
 			$this->symtbl->popScope();
diff --git a/SymbolTable.php b/SymbolTable.php
index c4f31da..b6d592a 100644
--- a/SymbolTable.php
+++ b/SymbolTable.php
@@ -115,11 +115,11 @@ public function isSymbol($candidate_string) {
 public function globalSymbolValue($name, &$value) {
 	$found_value = FALSE;
 	if (is_object($name)) {
-		debug_print_backtrace();
+		ob_start(); debug_print_backtrace(); fwrite(STDERR, rtrim(ob_get_clean() ?: "failed to dump backtrace") . PHP_EOL);
 	}
 	#fwrite(STDERR, "+++++\nglobalSymbolValue: ".print_r($name, TRUE)."\n-------\n");
 	if (!is_string($name) && !is_int($name)) {
-		debug_print_backtrace();
+		ob_start(); debug_print_backtrace(); fwrite(STDERR, rtrim(ob_get_clean() ?: "failed to dump backtrace") . PHP_EOL);
 		fwrite(STDERR, "Bad array name in globalSymbolValue:\n");
 		fwrite(STDERR, print_r($name, true));
 	}