说明：  D 语言编程参考手册(上).pdf D 语言既有 C 语言的强大威力，又有 Python 和 Ruby 的开发效率。它是一种集垃圾回收、手工内存操作、契约式设计、高级模板技术、内嵌汇编、内置单元测试、Mixin 风格多继承、类 Java 包管理机制、内置同步机制、内建基本运行时信息的系统级编程语言
(D programming language reference manual (on). Pdf D language of both the power of C language, Python and Ruby and the development efficiency. It is a collection garbage collection, hand-memory operation, Compact design, advanced template technology, embedded in the compilation, the built-unit testing, Mixin-style multiple inheritance, class Java package management mechanism, built-in synchronization mechanism, built-basic run-time information system-level programming language)