Info Catalog gnus: Topic Topology gnus: Group Topics

gnus: Topic Parameters

 
 2.16.5 Topic Parameters
 -----------------------
 
 All groups in a topic will inherit group parameters from the parent (and
 ancestor) topic parameters.  All valid group parameters are valid topic
 parameters (Group Parameters).  When the agent is enabled, all
 agent parameters (See Agent Parameters in Category Syntax) are
 also valid topic parameters.
 
    In addition, the following parameters are only valid as topic
 parameters:
 
 ‘subscribe’
      When subscribing new groups by topic (Subscription
      Methods), the ‘subscribe’ topic parameter says what groups go in
      what topic.  Its value should be a regexp to match the groups that
      should go in that topic.
 
 ‘subscribe-level’
      When subscribing new groups by topic (see the ‘subscribe’
      parameter), the group will be subscribed with the level specified
      in the ‘subscribe-level’ instead of
      ‘gnus-level-default-subscribed’.
 
    Group parameters (of course) override topic parameters, and topic
 parameters in sub-topics override topic parameters in super-topics.  You
 know.  Normal inheritance rules.  (“Rules” is here a noun, not a verb,
 although you may feel free to disagree with me here.)
 
      Gnus
        Emacs
           3: comp.emacs
           2: alt.religion.emacs
         452: alt.sex.emacs
          Relief
           452: alt.sex.emacs
             0: comp.talk.emacs.recovery
        Misc
           8: comp.binaries.fractals
          13: comp.sources.unix
         452: alt.sex.emacs
 
    The ‘Emacs’ topic has the topic parameter ‘(score-file .
 "emacs.SCORE")’; the ‘Relief’ topic has the topic parameter ‘(score-file
 . "relief.SCORE")’; and the ‘Misc’ topic has the topic parameter
 ‘(score-file . "emacs.SCORE")’.  In addition,
 ‘alt.religion.emacs’ has the group parameter ‘(score-file .
 "religion.SCORE")’.
 
    Now, when you enter ‘alt.sex.emacs’ in the ‘Relief’ topic, you will
 get the ‘relief.SCORE’ home score file.  If you enter the same group in
 the ‘Emacs’ topic, you’ll get the ‘emacs.SCORE’ home score file.  If you
 enter the group ‘alt.religion.emacs’, you’ll get the ‘religion.SCORE’
 home score file.
 
    This seems rather simple and self-evident, doesn’t it?  Well, yes.
 But there are some problems, especially with the ‘total-expiry’
 parameter.  Say you have a mail group in two topics; one with
 ‘total-expiry’ and one without.  What happens when you do ‘M-x
 gnus-expire-all-expirable-groups’?  Gnus has no way of telling which one
 of these topics you mean to expire articles from, so anything may
 happen.  In fact, I hereby declare that it is “undefined” what happens.
 You just have to be careful if you do stuff like that.
 

Info Catalog gnus: Topic Topology gnus: Group Topics