PHP，即“PHP: Hypertext Preprocessor”，是一种被广泛使用的开放源代码多用途脚本语言，尤其适用于 web 开发并可以嵌入到 HTML 中去。其语法利用了 C，Java 和 Perl，非常容易学习。该语言的主要目标是让 web 开发人员可以很快写出动态生成的网页，但 PHP 的功能远不止如此。
Anyone who has ever read a piece of C source code has seen them—the preprocessor directives. For example, you can find include directives (#include) at the beginning of most source files. The preprocessor is a system that rewrites the source before
This is the second article in a two-piece series covering the preprocessor. In the previous article we covered the basics—object- and function-like macros, the include directive, conditional compilation, and ended with the two special directives #er
