Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:439
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
To: engine2@lists.zend.com
Cc: internals@lists.php.net
In-Reply-To: <1048781764.25691.593.camel@localhost>
References: <1048781764.25691.593.camel@localhost>
Content-Type: multipart/mixed; boundary="=-94exCCO0kI8AQb/7FVwo"
Organization: 
Message-ID: <1048871727.25691.664.camel@localhost>
Mime-Version: 1.0
Date: 28 Mar 2003 18:15:27 +0100
Subject: Re: [Zend Engine 2] Type hints revisited [IllegalArgumentException
	instead of E_ERROR]
From: thekid@thekid.de (Timm Friebe)

--=-94exCCO0kI8AQb/7FVwo
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

On Thu, 2003-03-27 at 17:16, Timm Friebe wrote:
> I've implemented an additional feature for type hints that will throw an
> exception instead of bailing out in case an incorrect type is passed.
[...LONG disussion...]

After reading through a bunch of mails this generated, I get the idea
that most people here would be happier with an E_WARNING and the
function not being executed.

That gives:
- the OOP purist the possibility to throw an exception (in a userland
  error handler)
- the SOAP server a way to nicely recover
- the API designer a way to tell the user (s)he's messed up
- the "standard" programmer what (s)he's used to (PHP is quite
  forgiving in the way it handles incorrect argument types and
  usually warns about this)

Attached is the E_WARNING variant, an example script and its output.

- Timm

--=-94exCCO0kI8AQb/7FVwo
Content-Disposition: attachment; filename=zend_hints_warning.diff
Content-Type: text/x-patch; name=zend_hints_warning.diff; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

Index: Zend/ZEND_CHANGES
===================================================================
RCS file: /repository/ZendEngine2/ZEND_CHANGES,v
retrieving revision 1.55
diff -u -r1.55 ZEND_CHANGES
--- Zend/ZEND_CHANGES	7 Mar 2003 16:45:41 -0000	1.55
+++ Zend/ZEND_CHANGES	28 Mar 2003 17:09:53 -0000
@@ -177,6 +177,10 @@
           function b(Bar $bar) {
             // ...
           }
+          
+          function c([Bar] $bar) {
+            // ...
+          }
         }
 
         $a = new FooBar;
@@ -184,10 +188,14 @@
 
         $a->a($b);
         $a->b($b);
+        $a->c($b);
+        $a->c(NULL);
         ?>
 
       These class type hints are not checked upon compilation, as would
-      be the case in a typed language, but during runtime.
+      be the case in a typed language, but during runtime. Type hints in
+      square brackets (as seen in function "c") denote passing of NULL is
+      also allowed.
 
       This means that
 
@@ -202,6 +210,21 @@
             die('Argument 1 must be an instance of ClassName');
           }
         }
+        
+      and
+
+        function foo([ClassName] $object) {
+          // ...
+        }
+
+      is equivalent to
+
+        function foo($object) {
+          if (!is_null($object) && !($object instanceof ClassName)) {
+            die('Argument 1 must be an instance of ClassName');
+          }
+        }
+      .
 
       This syntax only applies to objects/classes, not built-in types.
 
Index: Zend/zend_execute.c
===================================================================
RCS file: /repository/ZendEngine2/zend_execute.c,v
retrieving revision 1.449
diff -u -r1.449 zend_execute.c
--- Zend/zend_execute.c	27 Mar 2003 17:57:47 -0000	1.449
+++ Zend/zend_execute.c	28 Mar 2003 17:09:54 -0000
@@ -4011,9 +4011,22 @@
 {
 	zval *arg = get_zval_ptr(&EX(opline)->op2, EX(Ts), &EG(free_op2), BP_VAR_R);
 	zend_class_entry *ce = EX_T(EX(opline)->op1.u.var).EA.class_entry;
+	int allowed;
+	
+	switch (Z_TYPE_P(arg)) {
+		case IS_OBJECT:
+			allowed= instanceof_function(Z_OBJCE_P(arg), ce TSRMLS_CC);
+			break;
+			
+		case IS_NULL:
+			allowed= (EX(opline)->op1.op_type == IS_VAR);
+			break;
+			
+		default: 
+			allowed= 0;
+	}
 
-	if ((Z_TYPE_P(arg) != IS_OBJECT)
-		|| !instanceof_function(Z_OBJCE_P(arg), ce TSRMLS_CC)) {
+	if (!allowed) {
 		char *error_msg;
 
 		if (ce->ce_flags & ZEND_ACC_INTERFACE) {
@@ -4021,7 +4034,9 @@
 		} else {
 			error_msg = "be an instance of";
 		}
-		zend_error(E_ERROR, "Argument %d must %s %s", EX(opline)->extended_value, error_msg, ce->name);
+		
+		zend_error(E_WARNING, "Argument %d must %s %s", EX(opline)->extended_value, error_msg, ce->name);
+		RETURN_FROM_EXECUTE_LOOP(execute_data);
 	}
 
 	NEXT_OPCODE();
Index: Zend/zend_language_parser.y
===================================================================
RCS file: /repository/ZendEngine2/zend_language_parser.y,v
retrieving revision 1.105
diff -u -r1.105 zend_language_parser.y
--- Zend/zend_language_parser.y	26 Mar 2003 20:42:23 -0000	1.105
+++ Zend/zend_language_parser.y	28 Mar 2003 17:09:55 -0000
@@ -453,7 +453,8 @@
 
 optional_class_type:
 		/* empty */		{ $$.op_type = IS_UNUSED; }
-	|	fully_qualified_class_name		{ $$ = $1; }
+	|	fully_qualified_class_name			{ $$ = $1; $$.op_type = IS_CONST; }
+	|	'[' fully_qualified_class_name ']'	{ $$ = $2; $$.op_type = IS_VAR; }
 ;
 
 function_call_parameter_list:

--=-94exCCO0kI8AQb/7FVwo
Content-Disposition: attachment; filename=hints.php
Content-Type: application/x-php; name=hints.php
Content-Transfer-Encoding: 7bit

<?php
  class Date { 
    private
      $utime    = 0;
      
    public function __construct($arg= -1) {
      if (is_int($arg)) {
        $this->utime= $arg < 0 ? time() : $arg;
      } else {
        $this->utime= strtotime($arg);
      }
    }
    
    public function toString($fmt= 'r') {
      return date($fmt, $this->utime);
    }
  }
  
  class Revision { 
    public
      $version    = 0,
      $author     = '',
      $date       = NULL;
      
    public function __construct($version, $author, [Date] $date= NULL) {
      $this->version= $version;
      $this->author= $author;
      $this->date= $date ? $date : new Date();
    }
    
    public function getDate() {
      return $this->date;
    }
  }
  
  class Article {
    public
      $created_at = NULL,
      $lastchange = NULL,
      $revisions  = array();
      
    public function setCreated_at(Date $date) { 
      $this->created_at= $date;
    }
    
    public function addRevision(Revision $revision) {
      $this->revisions[]= $revision;
      return $revision;
    }

    public function setLastchange([Date] $date) { 
      $this->lastchange= $date;
    }
  }
  
  $a= new Article();
  $a->setLastchange(new Date());
  $a->setLastchange(NULL);              // Passes
  $a->setCreated_at(new Date());
  
  $a->setCreated_at(NULL);              // Fails
  
  var_dump($a);
  
  var_dump($a->addRevision(new Revision(1, 'timm'))->getDate()->toString());

  // Pass 0 as value for date parameter
  $date= $a->addRevision(new Revision(2, 'foo', 0))->getDate();

  var_dump($date);  // Prints "NULL"
?>

--=-94exCCO0kI8AQb/7FVwo
Content-Disposition: attachment; filename=hints.php.out
Content-Type: text/plain; name=hints.php.out; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit


Warning: Argument 1 must be an instance of date in /usr/home/thekid/devel/php/hints.php on line 42
object(article)#1 (3) {
  ["created_at"]=>
  object(date)#2 (1) {
    [""]=>
    int(1048871463)
  }
  ["lastchange"]=>
  NULL
  ["revisions"]=>
  array(0) {
  }
}
string(31) "Fri, 28 Mar 2003 18:11:03 +0100"

Warning: Argument 3 must be an instance of date in /usr/home/thekid/devel/php/hints.php on line 25
NULL

--=-94exCCO0kI8AQb/7FVwo--