1. A listing of supported lexer types follows.

2. CHINESE_VGRAM: A lexer for extracting tokens from Chinese text.

3. JAPANESE_VGRAM: A lexer for extracting tokens from Japanese text.

4. For lexing purposes, this means that the lexer definition of an integer number, for example, can be used to build the lexer definition of a real number and a fraction.

5. This does mean that the lexer and the parser both have to know that an empty line separates a header from a body.

6. The lexer for this example is more complicated than the one for the calculator; quite a bit so.

7. The lexer actually does some of the work of figuring out where in a message it is, but the parser still ties everything together.

8. A good lexer example can help a lot with learning how to write a tokenizer.

9. Similarly, the lexer has to know about the structure of continuations; the parser only knows that it sometimes gets additional text to add on to a header.

10. A lexer is a software component that divides text strings into individual words, or tokens, so that the individual words can be indexed.

11. Whenever possible, try to develop separate tests for your lexer and your parser.

12. For instance, if you have a %union declaration that includes both integer and pointer values, and you declare a token to use the pointer value, but your lexer fills in the integer value...

13. So, in this example, NUMBER is a terminal; the lexer is producing this result.

14. That's the reason, why the Wave preprocessor library contains also an IDL lexer.

15. These directives are used to define the tokens the lexer can return.

16. These numbers will be outside the range of possible valid characters; thus, the lexer can return individual characters as themselves(), or special tokens using these defined values.

17. The Gang advocates abandoning your core language and building an entirely new one atop it, creating your own lexer, parser, grammar, and so on.

18. Jumpstart your yacc...and lex too! (developerWorks, November 2000) gives some more introductory background on everyone's favorite lexer/parser combo, and also has an example of a wordcount program.

19. It uses start states -- a feature allowing the lexer to match some rules only some of the time.

20. Thus, P::RD on top of Perl 5 is a powerful parser and lexer combination.

21. The tokens ALPHA, INT, and REAL are typically provided from the lexer.