Base antlr4 framework,build DSL engine

基于antlr4，编写一个dsl的引擎

micro server

设计gateway的时候，我就发现路由的规则，会经常发生变化，比如有时候对接业务，今天想要连接的是这个微服务，明天因为版本升级需要切换，如果假设硬编写代码可以完成，但是需要额外的升级gateway，这个就给我带来非常大的成本；另一方面，分发的规则，docker的container的伸缩性，我们想要不同节点接受，所以想要引入DSL的语法，能够借助更多人的帮助，帮我们的gateway更加健壮性，比如数据分析师、运维工程师等，使用一套大家都能够接受的简单语法，然后通过解释器去形成规则。

To go places and do things that have never been done before – that’s what living is all about.

Space, the final frontier. These are the voyages of the Starship Enterprise. Its five-year mission: to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no man has gone before.

As I stand out here in the wonders of the unknown at Hadley, I sort of realize there’s a fundamental truth to our nature, Man must explore, and this is exploration at its greatest.

Placeholder text by Space Ipsum. Photographs by NASA on The Commons.