Introduction - If you have any usage issues, please Google them yourself
The design of a scanner, the scanner is a subroutine, the input source string, each one call to identify and output a word symbol. In order to avoid advanced search to improve operational efficiency, simplify the design of the scanner, assuming that the programming language, the basic word (also known as keywords) can not do general identifiers, basic words, identifiers, and constants to determine operator or boundary operator for the interval with a blank interval.