Correct replace_outside_quotes error handling

idiorm.php

@@ -1459,8 +1459,9 @@ protected function _str_replace_outside_quotes(){
                 )*                          # Zero or more string chunks.
                 \z                          # Anchor to end of string.
                 /sx';
-            if (!preg_match($re_valid, $this->subject)) // Exit if string is invalid.
-                exit("Error! String not valid.");
+            if (!preg_match($re_valid, $this->subject)) {
+                throw new IdiormStringException("Subject string is not valid in the replace_outside_quotes context.");
+            }
             $re_parse = '/
                 # Match one chunk of a valid string having embedded quoted substrings.
                   (                         # Either $1: Quoted chunk.
@@ -1487,4 +1488,9 @@ protected function _str_replace_outside_quotes_cb($matches) {
             return preg_replace('/'. preg_quote($this->search, '/') .'/',
                 $this->replace, $matches[2]);
         }
-    }
+    }
+
+    /**
+     * A placeholder for exceptions eminating from the IdiormString class
+     */
+    class IdiormStringException {}