[Appendix D] D.8 Additional Regular Expression Features
Author: Randal L. Schwartz, Erik Olson & Tom Christiansen
Date: 1999-07-02T01:38:25Z

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| Appendix D Topics We Didn't Mention |

## D.8 Additional Regular Expression Features

Regular expressions can contain extended syntax (where whitespace is optional, so a regular expression can be split over multiple lines, and can contain regular Perl comments), and can have positive and negative lookahead. The syntax is a bit ugly, so rather than scare you off here, go look in Programming Perl, or see the perlre documentation. Jeffrey Friedl's book, Mastering Regular Expressions (published by O'Reilly & Associates), explains all of this and much more.

D.7 Symbol Table Manipulation With *FRED |  | D.9 Packages