Another use case could be, that you are simply not
interested in postings about christmas.
- /christmas([-_ ]?(tree|time|eve|pudding))?/
+ /christmas([-_ ]?(?:tree|time|eve|pudding))?/
+
+
+ATTENTION:
+
+It is absolutely important, that you use grouping
+parantheses instead of capturing parantheses!!
+
+Grouping parantheses are:
+
+ (?: )
+
+If you use capturing parantheses, which are
+
+ ( )
+
+it will produce errors and the regex won't work and
+at least your targets will not get collapsed.
+
3)