Index: lang.base.php
===================================================================
--- lang.base.php	(revision 6237)
+++ lang.base.php	(working copy)
@@ -51,19 +51,11 @@
     function errorAt($file, $line= -1) {
       $errors= &xp::registry('errors');
       
-      // If no line is requested, this is O(n)
+      // If no line is requested, we check for an error in the file
       if ($line < 0) return !empty($errors[$file]);
       
-      // Else, we'll have to search...
-      if (isset($errors[$file])) for (
-        $i= 0, $s= sizeof($errors[$file]); 
-        $i < $s; 
-        $i++
-      ) {
-        if ($line == $errors[$file][$i][2]) return TRUE;
-      }
-      
-      return FALSE;
+      // Else, we also take the line number into account
+      return !empty($errors[$file][$line]);
     }
     // }}}
     
@@ -149,7 +141,7 @@
     if (0 == error_reporting() || is_null($file)) return;
 
     $errors= &xp::registry('errors');
-    $errors[$file][]= array($code, $msg, $line);
+    @$errors[$file][$line][$msg]++;
     xp::registry('errors', $errors);
   }
   // }}}
Index: lang/Throwable.class.php
===================================================================
--- lang/Throwable.class.php	(revision 6237)
+++ lang/Throwable.class.php	(working copy)
@@ -26,25 +26,27 @@
      */
     function __construct($message) {
       static $except= array(
-        'call_user_func_array', 'call_user_func', 'object', '__call', '__set', '__get'
+        'call_user_func_array'  => 1, 
+        'call_user_func'        => 1, 
+        'object'                => 1
       );
       $this->message= $message;
       
       $errors= xp::registry('errors');
-      foreach (debug_backtrace() as $trace) {
-        if (!isset($trace['function']) || in_array($trace['function'], $except)) continue;
+      foreach (debug_backtrace() as $no => $trace) {
+        if (!isset($trace['function']) || isset($except[$trace['function']])) continue;
 
         // Pop error messages off the copied error stack
         if (isset($trace['file']) && isset($errors[$trace['file']])) {
           $messages= $errors[$trace['file']];
           unset($errors[$trace['file']]);
         } else {
-          $messages= array();
+          $messages= array(array('' => 1));
         }
 
         // Not all of these are always set: debug_backtrace() should
         // initialize these - at least - to NULL, IMO => Workaround.
-        $this->trace[]= &new StackTraceElement(
+        $this->addStackTraceFor(
           isset($trace['file']) ? $trace['file'] : NULL,
           isset($trace['class']) ? $trace['class'] : NULL,
           isset($trace['function']) ? $trace['function'] : NULL,
@@ -60,18 +62,46 @@
           ? strtolower(substr(basename($key), 0, -10))
           : '<main>'
         );
-        for ($i= 0, $s= sizeof($errors[$key]); $i < $s; $i++) { 
-          $this->trace[]= &new StackTraceElement(
-            $key,
+        
+        foreach ($errors as $file => $list) {
+          $this->addStackTraceFor(
+            $file,
             $class,
             NULL,
-            $errors[$key][$i][2],
+            NULL,
             array(),
-            array($errors[$key][$i])
+            $list
           );
         }
       }
     }
+    
+    /**
+     * Adds new stacktrace elements to the internal list of stacktrace
+     * elements, each for one error.
+     *
+     * @access  protected
+     * @param   string file
+     * @param   string class
+     * @param   string function
+     * @param   int originalline
+     * @param   mixed[] args
+     * @param   mixed[] errors
+     */
+    function addStackTraceFor($file, $class, $function, $originalline, $args, $errors) {
+      foreach ($errors as $line => $errormsg) {
+        foreach ($errormsg as $message => $amount) {
+          $this->trace[]= &new StackTraceElement(
+            $file,
+            $class,
+            $function,
+            $originalline ? $originalline : $line,
+            $args,
+            $message.($amount > 1 ? ' (... '.($amount - 1).' more)' : '')
+          );
+        }   
+      }
+    }
 
     /**
      * Get Message
@@ -128,7 +158,7 @@
         $this->message
       );
       for ($i= 0, $t= sizeof($this->trace); $i < $t; $i++) {
-        $s.= $this->trace[$i]->toString();
+        $s.= $this->trace[$i]->toString(); 
       }
       return $s;
     }
Index: lang/StackTraceElement.class.php
===================================================================
--- lang/StackTraceElement.class.php	(revision 6237)
+++ lang/StackTraceElement.class.php	(working copy)
@@ -18,7 +18,7 @@
       $method   = '',
       $line     = 0,
       $args     = array(),
-      $messages = array();
+      $message  = '';
       
     /**
      * Constructor
@@ -29,15 +29,15 @@
      * @param   string method
      * @param   int line
      * @param   array args
-     * @param   array messages
+     * @param   string message
      */
-    function __construct($file, $class, $method, $line, $args, $messages) {
+    function __construct($file, $class, $method, $line, $args, $message) {
       $this->file     = $file;  
       $this->class    = $class; 
       $this->method   = $method;
       $this->line     = $line;
       $this->args     = $args;
-      $this->messages = $messages;
+      $this->message  = $message;
     }
     
     /**
@@ -71,29 +71,15 @@
           }
         }
       }
-      $fmt= sprintf(
-        "  at %s::%s(%s) [line %%3\$d of %s] %%2\$s\n",
+      return sprintf(
+        "  at %s::%s(%s) [line %d of %s] %s\n",
         isset($this->class) ? xp::nameOf($this->class) : '<main>',
         isset($this->method) ? $this->method : '<main>',
         implode(', ', $args),
-        basename(isset($this->file) ? $this->file : __FILE__)
+        $this->line,
+        basename(isset($this->file) ? $this->file : __FILE__),
+        $this->message
       );
-      
-      if (!$this->messages) {
-        return sprintf(
-          $fmt, 
-          E_USER_NOTICE, 
-          '', 
-          isset($this->line) ? $this->line : __LINE__
-        );
-      }
-      
-      $str= '';
-      for ($i= 0, $s= sizeof($this->messages); $i < $s; $i++) {
-        $str.= rtrim(vsprintf($fmt, $this->messages[$i]))."\n";
-      }
-      return $str;
     }
-  
   }
 ?>