一个简单的编译器，可以实现简单的画图语句的解析，最终画出简单的图形。涉及程序编译器的实现几个步骤，词法分析，语法分析，语义分析，等等。-a simple compiler can achieve a simple drawing of analytic statement, the final draw simple graphics. The procedures compiler in several steps, lexical analysis, grammar analysis, semantic analysis, and so on.