cvs: phpweb / zend-engine-2.php
| From: | Sterling Hughes | Date: | Wed, 25 Jun 2003 03:43:56 +0000 |
| Subject: | cvs: phpweb / zend-engine-2.php | ||
| Groups: | php.mirrors | ||
| Request: | Send a blank email to php-mirrors+get-18929@lists.php.net to get a copy of this message | ||
sterling Tue Jun 24 23:43:56 2003 EDT
Modified files:
/phpweb zend-engine-2.php
Log:
a few fixes, grammar and style
Index: phpweb/zend-engine-2.php diff -u phpweb/zend-engine-2.php:1.2 phpweb/zend-engine-2.php:1.3 --- phpweb/zend-engine-2.php:1.2 Tue Jun 24 23:17:26 2003 +++ phpweb/zend-engine-2.php Tue Jun 24 23:43:56 2003 @@ -5,26 +5,21 @@ ?> <h2>New Object Model.</h2> <p> -The Zend Engine's handling of objects has been completely changed in -order to allow for new features, but also to increase its performance. -Objects were handled in previous versions like primitive types (for -instance integers and strings). The drawback of this method is, that -semantically the whole object was copied when a variable was assigned -or parameters were passed to a method. The new approach refers to -objects by handle and not by value (one can think of a handle as an -object's ID). +PHP's handling of objects has been completely rewritten, allowing for better performance and more +features. In previous versions of PHP, objects were handled like primitive types (for +instance integers and strings). The drawback of this method was that semantically the whole object +was copied when a variable was assigned, or pass as a parameter to a method. In the new approach, +objects are referenced by handle, and not by value (one can think of a handle as an object's +identifier). </p> <p> -Many PHP programmers aren't even aware of the copying quirks of the old -object model and, therefore, there is a relatively good chance that the -amount of PHP applications that will work out of the box or after a very -small amount of modifications would be high. +Many PHP programmers aren't even aware of the copying quirks of the old object model and, therefore, +the majority of PHP applications will work out of the box, or with very few modifications. </p> <h2>Private and Protected Members</h2> <p> -The Zend Engine 2.0 introduces private and protected member variables. -Note that for performance reasons no error message is emitted in case of an -illegal access to a private or protectecd member variable. +PHP5 introduces private and protected member variables, they allow do define the visibility of class +properties. </p> <h3>Example</h3> @@ -74,7 +69,7 @@ <h2>Private and protected methods</h2> <p> -The Zend Engine 2.0 introduces private and protected methods. +With PHP5 (Zend Engine 2), private and protected methods are also introduced. </p> <h3>Example</h3> @@ -110,10 +105,9 @@ <h2>Abstract Classes and Methods</h2> <p> -The Zend Engine 2.0 introduces abstract classes and methods. An abstract -method only declares the method's signature and does not provide an -implementation. A class that contains abstract methods needs to be declared -abstract. +PHP5 also introduces abstract classes and methods. An abstract method only declares the +method's signature and does not provide an implementation. A class that contains abstract +methods needs to be declared abstract. </p> <h3>Example</h3> <p> @@ -165,9 +159,8 @@ <h2>Class Type Hints</h2> <p> -While remaining loosely typed the Zend Engine 2.0 introduces the ability to use -class type hints to declare the expected class of objects that are passed as -parameters to a method. +While remaining loosely typed PHP5 introduces the ability to use class type hints to declare +the expected class of objects that are passed as parameters to a method. </p> <h3>Example</h3> <p> @@ -224,8 +217,8 @@ <h2>final</h2> <p> -The Zend Engine 2.0 introduces the "final" keyword to declare final members and -methods. Those cannot be overridden by sub-classes. +PHP5 introduces the "final" keyword to declare final members and methods. Methods and +members declared final cannot be overridden by sub-classes. </p> <h3>Example</h3> <p> @@ -240,9 +233,9 @@ </p> <h2>Object Cloning</h2> <p> -The Zend Engine 1.0 offered no way a user could decide what copy constructor to run -when an object is duplicated. During duplication, the Zend Engine 1.0 did a bitwise -copy making an identical replica of all the object's properties. +PHP4 (Zend Engine 1.0) offered no way a user could decide what copy constructor to run +when an object is duplicated. During duplication, PHP4 did a bit for bit copy making an +identical replica of all the object's properties. </p> <p> Creating a copy of an object with fully replicated properties is not always the wanted @@ -304,19 +297,17 @@ <p> The Zend Engine allows developers to declare constructor methods for classes. Classes which have a constructor method call this method on each newly-created object, so it is -suitable for any initialization that the object may need before it can be used. +suitable for any initialization that the object may need before it is used. </p> <p> -With the Zend Engine 1.0, constructor methods were class methods that had the same name as -the class itself. Since it is very common to call parent constructors from derived classes, -the way the Zend Engine 1.0 worked made it a bit cumbersome to move classes around in a large -class hierarchy. If a class is moved to reside under a different parent, the constructor name -of that parent changes as well, and the code in the derived class that calls the parent -constructor has to be modified. +With PHP4, constructor methods were class methods that had the same name as the class itself. Since +it is very common to call parent constructors from derived classes, the way PHP4 worked made it a bit +cumbersome to move classes around in a large class hierarchy. If a class is moved to reside under a +different parent, the constructor name of that parent changes as well, and the code in the derived class +that calls the parent constructor has to be modified. </p> <p> -The Zend Engine 2.0 introduces a standard way of declaring constructor methods by calling them -by the name __construct(). +PHP5 introduces a standard way of declaring constructor methods by calling them by the name <code>__construct()</code>. </p> <h3>Example</h3> <?php highlight_string('<?php @@ -337,7 +328,7 @@ $obj = new SubClass(); ?>'); ?> <p> -For backwards compatibility, if the Zend Engine 2.0 cannot find a <code>__construct()</code> function +For backwards compatibility, if PHP5 cannot find a <code>__construct()</code> function for a given class, it will search for the old-style constructor function, by the name of the class. Effectively, it means that the only case that would have compatibility issues is if the class had a method named <code>__construct()</code> which was used for different semantics. @@ -346,11 +337,11 @@ <p> Having the ability to define destructors for objects can be very useful. Destructors can log messages for debugging, close database connections and do other clean-up work. No mechanism for object destructors -existed in Zend Engine 1.0, although PHP had already support for registering functions which should be +existed in PHP4, although PHP had already support for registering functions which should be run on request shutdown. </p> <p> -Zend Engine 2.0 introduces a destructor concept similar to that of other object-oriented languages, such +PHP5 introduces a destructor concept similar to that of other object-oriented languages, such as Java: When the last reference to an object is destroyed the object's destructor, which is a class method name %__destruct()% that recieves no parameters, is called before the object is freed from memory. </p> @@ -378,7 +369,7 @@ </p> <h2>Constants</h2> <p> -Zend Engine 2.0 introduces per-class constants: +PHP5 introduces per-class constants: </p> <p> <?php highlight_string('<?php @@ -390,7 +381,7 @@ ?>'); ?> </p> <p> -Zend Engine 2.0 allows for expressions within constants, however, constants are evaluated at compile time, therefore +PHP5 allows for expressions within constants, however, constants are evaluated at compile time, therefore no constants can be declared that rely on runtime information. </p> <?php highlight_string('<?php @@ -406,7 +397,7 @@ </p> <h2>Exceptions</h2> <p> -Zend Engine 1.0 had no exception handling. Zend Engine 2.0 introduces a exception model similar to +PHP4 had no exception handling. PHP5 introduces a exception model similar to that of other programming languages. </p> <h3>Example</h3> @@ -431,7 +422,7 @@ </p> <h2>Dereferencing objects returned from functions</h2> <p> -In Zend Engine 1.0 it wasn't possible to dereference objects returned by functions and make further +In PHP4 it wasn't possible to dereference objects returned by functions and make further method calls on those objects. With the advent of Zend Engine 2, the following is now possible: </p> <p> @@ -474,7 +465,7 @@ </p> <h2>Static Methods</h2> <p> -The Zend Engine 2.0 introduces the 'static' keyword to declare a method static, thus +PHP5 introduces the 'static' keyword to declare a method static, thus callable from outside the object context. </p> <h3>Example</h3> @@ -494,7 +485,7 @@ </p> <h2>instanceof</h2> <p> -Zend Engine 2 introduces the <code>instanceof</code> keyword, that allows you to ascertain whether +PHP5 introduces the <code>instanceof</code> keyword, that allows you to ascertain whether or not an object is an instance of a class, or extends a class, or implements an interface. </p> <h3>Example</h3> @@ -527,7 +518,7 @@ </p> <h2>__autoload()</h2> <p> -The __autoload() interceptor function will be automatically called when an undeclared class +The <code>__autoload()</code> interceptor function will be automatically called when an undeclared class is to be instantiated. The name of that class will be passed to the __autoload() interceptor function as its only argument. </p>
Index: phpweb/zend-engine-2.php diff -u phpweb/zend-engine-2.php:1.2 phpweb/zend-engine-2.php:1.3 --- phpweb/zend-engine-2.php:1.2 Tue Jun 24 23:17:26 2003 +++ phpweb/zend-engine-2.php Tue Jun 24 23:43:56 2003 @@ -5,26 +5,21 @@ ?> <h2>New Object Model.</h2> <p> -The Zend Engine's handling of objects has been completely changed in -order to allow for new features, but also to increase its performance. -Objects were handled in previous versions like primitive types (for -instance integers and strings). The drawback of this method is, that -semantically the whole object was copied when a variable was assigned -or parameters were passed to a method. The new approach refers to -objects by handle and not by value (one can think of a handle as an -object's ID). +PHP's handling of objects has been completely rewritten, allowing for better performance and more +features. In previous versions of PHP, objects were handled like primitive types (for +instance integers and strings). The drawback of this method was that semantically the whole object +was copied when a variable was assigned, or pass as a parameter to a method. In the new approach, +objects are referenced by handle, and not by value (one can think of a handle as an object's +identifier). </p> <p> -Many PHP programmers aren't even aware of the copying quirks of the old -object model and, therefore, there is a relatively good chance that the -amount of PHP applications that will work out of the box or after a very -small amount of modifications would be high. +Many PHP programmers aren't even aware of the copying quirks of the old object model and, therefore, +the majority of PHP applications will work out of the box, or with very few modifications. </p> <h2>Private and Protected Members</h2> <p> -The Zend Engine 2.0 introduces private and protected member variables. -Note that for performance reasons no error message is emitted in case of an -illegal access to a private or protectecd member variable. +PHP5 introduces private and protected member variables, they allow do define the visibility of class +properties. </p> <h3>Example</h3> @@ -74,7 +69,7 @@ <h2>Private and protected methods</h2> <p> -The Zend Engine 2.0 introduces private and protected methods. +With PHP5 (Zend Engine 2), private and protected methods are also introduced. </p> <h3>Example</h3> @@ -110,10 +105,9 @@ <h2>Abstract Classes and Methods</h2> <p> -The Zend Engine 2.0 introduces abstract classes and methods. An abstract -method only declares the method's signature and does not provide an -implementation. A class that contains abstract methods needs to be declared -abstract. +PHP5 also introduces abstract classes and methods. An abstract method only declares the +method's signature and does not provide an implementation. A class that contains abstract +methods needs to be declared abstract. </p> <h3>Example</h3> <p> @@ -165,9 +159,8 @@ <h2>Class Type Hints</h2> <p> -While remaining loosely typed the Zend Engine 2.0 introduces the ability to use -class type hints to declare the expected class of objects that are passed as -parameters to a method. +While remaining loosely typed PHP5 introduces the ability to use class type hints to declare +the expected class of objects that are passed as parameters to a method. </p> <h3>Example</h3> <p> @@ -224,8 +217,8 @@ <h2>final</h2> <p> -The Zend Engine 2.0 introduces the "final" keyword to declare final members and -methods. Those cannot be overridden by sub-classes. +PHP5 introduces the "final" keyword to declare final members and methods. Methods and +members declared final cannot be overridden by sub-classes. </p> <h3>Example</h3> <p> @@ -240,9 +233,9 @@ </p> <h2>Object Cloning</h2> <p> -The Zend Engine 1.0 offered no way a user could decide what copy constructor to run -when an object is duplicated. During duplication, the Zend Engine 1.0 did a bitwise -copy making an identical replica of all the object's properties. +PHP4 (Zend Engine 1.0) offered no way a user could decide what copy constructor to run +when an object is duplicated. During duplication, PHP4 did a bit for bit copy making an +identical replica of all the object's properties. </p> <p> Creating a copy of an object with fully replicated properties is not always the wanted @@ -304,19 +297,17 @@ <p> The Zend Engine allows developers to declare constructor methods for classes. Classes which have a constructor method call this method on each newly-created object, so it is -suitable for any initialization that the object may need before it can be used. +suitable for any initialization that the object may need before it is used. </p> <p> -With the Zend Engine 1.0, constructor methods were class methods that had the same name as -the class itself. Since it is very common to call parent constructors from derived classes, -the way the Zend Engine 1.0 worked made it a bit cumbersome to move classes around in a large -class hierarchy. If a class is moved to reside under a different parent, the constructor name -of that parent changes as well, and the code in the derived class that calls the parent -constructor has to be modified. +With PHP4, constructor methods were class methods that had the same name as the class itself. Since +it is very common to call parent constructors from derived classes, the way PHP4 worked made it a bit +cumbersome to move classes around in a large class hierarchy. If a class is moved to reside under a +different parent, the constructor name of that parent changes as well, and the code in the derived class +that calls the parent constructor has to be modified. </p> <p> -The Zend Engine 2.0 introduces a standard way of declaring constructor methods by calling them -by the name __construct(). +PHP5 introduces a standard way of declaring constructor methods by calling them by the name <code>__construct()</code>. </p> <h3>Example</h3> <?php highlight_string('<?php @@ -337,7 +328,7 @@ $obj = new SubClass(); ?>'); ?> <p> -For backwards compatibility, if the Zend Engine 2.0 cannot find a <code>__construct()</code> function +For backwards compatibility, if PHP5 cannot find a <code>__construct()</code> function for a given class, it will search for the old-style constructor function, by the name of the class. Effectively, it means that the only case that would have compatibility issues is if the class had a method named <code>__construct()</code> which was used for different semantics. @@ -346,11 +337,11 @@ <p> Having the ability to define destructors for objects can be very useful. Destructors can log messages for debugging, close database connections and do other clean-up work. No mechanism for object destructors -existed in Zend Engine 1.0, although PHP had already support for registering functions which should be +existed in PHP4, although PHP had already support for registering functions which should be run on request shutdown. </p> <p> -Zend Engine 2.0 introduces a destructor concept similar to that of other object-oriented languages, such +PHP5 introduces a destructor concept similar to that of other object-oriented languages, such as Java: When the last reference to an object is destroyed the object's destructor, which is a class method name %__destruct()% that recieves no parameters, is called before the object is freed from memory. </p> @@ -378,7 +369,7 @@ </p> <h2>Constants</h2> <p> -Zend Engine 2.0 introduces per-class constants: +PHP5 introduces per-class constants: </p> <p> <?php highlight_string('<?php @@ -390,7 +381,7 @@ ?>'); ?> </p> <p> -Zend Engine 2.0 allows for expressions within constants, however, constants are evaluated at compile time, therefore +PHP5 allows for expressions within constants, however, constants are evaluated at compile time, therefore no constants can be declared that rely on runtime information. </p> <?php highlight_string('<?php @@ -406,7 +397,7 @@ </p> <h2>Exceptions</h2> <p> -Zend Engine 1.0 had no exception handling. Zend Engine 2.0 introduces a exception model similar to +PHP4 had no exception handling. PHP5 introduces a exception model similar to that of other programming languages. </p> <h3>Example</h3> @@ -431,7 +422,7 @@ </p> <h2>Dereferencing objects returned from functions</h2> <p> -In Zend Engine 1.0 it wasn't possible to dereference objects returned by functions and make further +In PHP4 it wasn't possible to dereference objects returned by functions and make further method calls on those objects. With the advent of Zend Engine 2, the following is now possible: </p> <p> @@ -474,7 +465,7 @@ </p> <h2>Static Methods</h2> <p> -The Zend Engine 2.0 introduces the 'static' keyword to declare a method static, thus +PHP5 introduces the 'static' keyword to declare a method static, thus callable from outside the object context. </p> <h3>Example</h3> @@ -494,7 +485,7 @@ </p> <h2>instanceof</h2> <p> -Zend Engine 2 introduces the <code>instanceof</code> keyword, that allows you to ascertain whether +PHP5 introduces the <code>instanceof</code> keyword, that allows you to ascertain whether or not an object is an instance of a class, or extends a class, or implements an interface. </p> <h3>Example</h3> @@ -527,7 +518,7 @@ </p> <h2>__autoload()</h2> <p> -The __autoload() interceptor function will be automatically called when an undeclared class +The <code>__autoload()</code> interceptor function will be automatically called when an undeclared class is to be instantiated. The name of that class will be passed to the __autoload() interceptor function as its only argument. </p>