====== Pattern ======

Patterns are declared from a class that extends [[https://javadoc.grogra.de/xl/de/grogra/xl/query/UserDefinedPattern.html|UserDefinedPattern]]. Each concrete subclass of UserDefinedPattern declares a user-defined pattern, where the term “user-defined” distinguishes such a pattern from built-in patterns of the XL programming language. The signature (number and types of parameters) of a user-defined pattern is given by a special method named signature which has no further purpose. The [[https://javadoc.grogra.de/xl/de/grogra/xl/query/UserDefinedPattern.In.html|@In]] and [[https://javadoc.grogra.de/xl/de/grogra/xl/query/UserDefinedPattern.Out.html|@Out]] annotations in the signature are needed when textually neighboring patterns are connected.

=====  =====


{{namespace>:01_user_documentation:07_rgg_xl:02_xl:08_object:02_pattern}}