背景：gpp 通用前处理器

GPP is a general-purpose preprocessor with customizable syntax, suitable for a wide range of preprocessing tasks. Its independence from any one programming language makes it much more versatile than the C preprocessor (cpp), while its syntax is lighter and more flexible than that of GNU m4. There are built-in macros for use with C/C++, LaTeX, HTML, XHTML, and Prolog files.