# XSL Rules | PMD Source Code Analyzer
Keywords: rule_referencesxsl,

# XSL Rules

Index of all built-in rules available for XSL

## Code Style

Rules which enforce a specific coding style.

- UseConcatOnce: The XPath concat() functions accepts as many arguments as required so you can have "concat($a,’b’…

## Performance

Rules that flag suboptimal code.

- AvoidAxisNavigation: Avoid using the ‘following’ or ‘preceding’ axes whenever possible, as these can cut through 100% …

## Additional rulesets

- XPath in XSL (`rulesets/xsl/xpath.xml`):

  Deprecated This ruleset is for backwards compatibility.

  It contains the following rules:

  AvoidAxisNavigation, UseConcatOnce

Tags: rule_references