Update

1 files changed, 86 insertions, 4 deletions

diff --git a/Zend/ZEND_CHANGES b/Zend/ZEND_CHANGES
index f0d5b1d503..6d4a814ca0 100644
--- a/Zend/ZEND_CHANGES
+++ b/Zend/ZEND_CHANGES
@@ -427,7 +427,20 @@ Changes in the Zend Engine 2.0
 
       The Zend Engine 1.0 had no exception handling. The Zend Engine 2.0
       introduces a exception model similar to that of other programming
-      languages.
+      languages. But there is no catch all and no finally clause.
+
+      Old code that has no user-defined classes or functions 'catch', 
+      'throw' and 'try' will run without modifications.
+      
+      Exceptions can be rethrown in catch blocks. Also it is possible to
+      have multiple catch blocks. In that case the caught exception is 
+      compare with the classtype of each catch block from top to bottom
+      and the first block that has a 'instanceof' match gets executed.
+      When the catch block finishes execution continues at the end of 
+      the last catch block. If no catch block has a 'instanceof' match
+      then the next try/catch block is searched until no more try/catch 
+      blocks are available. In that case the exception is an uncaught
+      exception and the program terminates with showing the exception.
 
       Example:
 
@@ -455,14 +468,81 @@ Changes in the Zend Engine 2.0
         try {
             throw new MyExceptionFoo('Hello');
         }
-
         catch (MyException $exception) {
             $exception->Display();
         }
+        catch (Exception $exception) {
+            echo $exception;
+        }
         ?>
+      
+      Even though the above example shows that it is possible to define
+      exception classes  that don't inherit from Exception it is best to
+      do so. This is because the internal Exception class can gather a
+      lot of information otherwise not available. The PHP code emulation
+      code would look something like shown below. The comments show the
+      meaning of each proerty and hence there getter methods. As the code
+      shows it is possible to read any available information by using the
+      getter methods. But since some og the methods are used internally
+      they are marked final. All in all the class is very restrictive 
+      because it must be ensured that anything used internally always
+      works as expected.
+      
+      Emulating class Exception:
 
-      Old code that has no user-defined classes or functions 'catch', 
-      'throw' and 'try' will run without modifications.
+        <?php
+        class Exception {
+          function __construct(string $message=NULL, int code=0) {
+            if (func_num_args()) {
+              $this->message = $message;
+            }
+            $this->code = $code;
+            $this->file = __FILE__; // of throw clause
+            $this->line = __LINE__; // of throw clause
+            $this->trace = debug_backtrace();
+            $this->string = StringFormat($this);
+          }
+          
+          protected $message = 'Unknown exception';  // exception message 
+          protected $code = 0; // user defined exception code
+          protected $file;     // source filename of exception
+          protected $line;     // source line of exception
+  
+          private $trace;      // backtrace of exception
+          private $string;     // internal only!!
+          
+          final function getMessage() {
+            return $this->message;
+          }
+          final function getCode() {
+            return $this->code;
+          }
+          final function getFile() {
+            return $this->file;
+          }
+          final function getTrace() {
+            return $this->trace;
+          }
+          final function getTraceAsString() {
+            return self::TraceFormat($this);
+          }
+          function _toString() {
+            return $this->string;
+          }
+          static private function StringFormat(Exception $exception) {
+            // ... a function not available in PHP scripts
+            // that returns all relevant information as a string
+          }
+          static private function TraceFormat(Exception $exception) {
+            // ... a function not available in PHP scripts
+            // that returns the backtrace as a string
+          }
+        }
+        ?>
+      
+      If you derive your exception classes from this Exception base class
+      your exceptions will be nicely shown in the builtin handler for 
+      uncaught exceptions.
 
     * Dereferencing objects returned from functions.
 
@@ -756,6 +836,8 @@ Changes in the Zend Engine 2.0
             $obj = Foo;
             
             $str = (string) $obj; // call __toString()
+            
+            echo $obj; // call __toString()
         ?>
 
     * Reflection API