这是一个公式编辑器，实现简单的功能，源于 编译原理 -This is a formula editor, the realization of simple functions, from compiler theory

复杂的公式编辑器，支持很多复杂的数学公式的绘制和导出成图片。-Editor complex formula to support a number of complex mathematical formulas and export the drawing into picture.