Zend Engine

Overview

Version 1.0 of the Zend Engine is the heart and brain of PHP 4.0. It provides the infrastructure and services to the function modules, and implements the language syntax. The Zend Engine 1.0 is actually the second revision of the PHP scripting engine; It’s still at large based on the same parsing rules as the PHP 3.0 engine (which was basically ‘Zend Engine 0.5’). While this allowed for a very easy migration path from PHP 3.0 to
4.0, it also limited the scope of language-level improvements, to the same ‘state of mind’ as PHP 3.0 was in. Thanks to the unprecedented success of PHP 3.0 and 4.0, a lot of feedback was received from developers, regarding the kinds of language features that they were either missing, or wanted to see improved. We feel that the time is right to start working towards a revision of the Zend Engine that would incorporate new features, improve existing ones, and provide solutions to some of the most difficult problems that PHP developers experience today. The purpose of this document is to provide the motivations for and in-depth description of each new feature, and is the base for the Zend Engine 2.0. Note, that the scope of the Zend Engine 2.0 is such that it can be implemented in a reasonable time frame. Future versions of the Zend Engine may and probably will