PHP 刚刚发布了 5.4 的第一个 alpha 测试版本，该版本主要改进包括：
新增: Traits language construct
新增: Array dereferencing support
新增: DTrace support
提升: Improved Zend Engine memory usage and performance
移动: ext/sqlite moved to pecl (sqlite3 support is still built-in)
删除的一些特性：
Removed: break/continue $var syntax
Removed: register_globals, allow_call_time_pass_reference, and register_long_arrays ini options
Removed: session_is_regisitered(), session_registered(), and session_unregister()