1.7.1. Regular Expression Functions1.7.2. Regular Expression Locale Support1.7.3. Regular Expression Matching Options1.7.4. Standards Compliance1.7.5. Differences Between Perl and Oracle1.7.5.1. String literal issues1.7.5.2. NULL versus empty strings1.7.5.3. Perl-specific syntax1.7.5.4. Syntax Perl does not support1.7.5.5. Negating character classes1.7.5.6. Lazy quantifiers (non-greediness)1.7.5.7. Experimental features1.7.5.8. Backreferences1.7.5.9. Backslash differences