Info Catalog gnus: Article Header gnus: Article Treatment gnus: Article Button Levels

gnus: Article Buttons

 
 3.18.6 Article Buttons
 ----------------------
 
 People often include references to other stuff in articles, and it would
 be nice if Gnus could just fetch whatever it is that people talk about
 with the minimum of fuzz when you hit ‘RET’ or use the middle mouse
 button on these references.
 
    Gnus adds “buttons” to certain standard references by default:
 Well-formed URLs, mail addresses, Message-IDs, Info links, man pages and
 Emacs or Gnus related references.  This is controlled by two variables,
 one that handles article bodies and one that handles article heads:
 
 ‘gnus-button-alist’
      This is an alist where each entry has this form:
 
           (REGEXP BUTTON-PAR USE-P FUNCTION DATA-PAR)
 
      REGEXP
           All text that match this regular expression (case insensitive)
           will be considered an external reference.  Here’s a typical
           regexp that matches embedded URLs: ‘<URL:\\([^\n\r>]*\\)>’.
           This can also be a variable containing a regexp, useful
           variables to use include ‘gnus-button-url-regexp’ and
           ‘gnus-button-mid-or-mail-regexp’.
 
      BUTTON-PAR
           Gnus has to know which parts of the matches is to be
           highlighted.  This is a number that says what sub-expression
           of the regexp is to be highlighted.  If you want it all
           highlighted, you use 0 here.
 
      USE-P
           This form will be ‘eval’ed, and if the result is non-‘nil’,
           this is considered a match.  This is useful if you want extra
           sifting to avoid false matches.  Often variables named
           ‘gnus-button-*-level’ are used here, Article Button
           Levels, but any other form may be used too.
 
      FUNCTION
           This function will be called when you click on this button.
 
      DATA-PAR
           As with BUTTON-PAR, this is a sub-expression number, but this
           one says which part of the match is to be sent as data to
           FUNCTION.
 
      So the full entry for buttonizing URLs is then
 
           ("<URL:\\([^\n\r>]*\\)>" 0 t gnus-button-url 1)
 
 ‘gnus-header-button-alist’
      This is just like the other alist, except that it is applied to the
      article head only, and that each entry has an additional element
      that is used to say what headers to apply the buttonize coding to:
 
           (HEADER REGEXP BUTTON-PAR USE-P FUNCTION DATA-PAR)
 
      HEADER is a regular expression.
 
 3.18.6.1 Related variables and functions
 ........................................
 
 ‘gnus-button-*-level’
      Article Button Levels.
 
 ‘gnus-button-url-regexp’
      A regular expression that matches embedded URLs.  It is used in the
      default values of the variables above.
 
 ‘gnus-button-man-handler’
      The function to use for displaying man pages.  It must take at
      least one argument with a string naming the man page.
 
 ‘gnus-button-mid-or-mail-regexp’
      Regular expression that matches a message ID or a mail address.
 
 ‘gnus-button-prefer-mid-or-mail’
      This variable determines what to do when the button on a string as
      ‘foo123@bar.invalid’ is pushed.  Strings like this can be either a
      message ID or a mail address.  If it is one of the symbols ‘mid’ or
      ‘mail’, Gnus will always assume that the string is a message ID or
      a mail address, respectively.  If this variable is set to the
      symbol ‘ask’, always query the user what to do.  If it is a
      function, this function will be called with the string as its only
      argument.  The function must return ‘mid’, ‘mail’, ‘invalid’ or
      ‘ask’.  The default value is the function
      ‘gnus-button-mid-or-mail-heuristic’.
 
 ‘gnus-button-mid-or-mail-heuristic’
      Function that guesses whether its argument is a message ID or a
      mail address.  Returns ‘mid’ if it’s a message IDs, ‘mail’ if it’s
      a mail address, ‘ask’ if unsure and ‘invalid’ if the string is
      invalid.
 
 ‘gnus-button-mid-or-mail-heuristic-alist’
      An alist of ‘(RATE . REGEXP)’ pairs used by the function
      ‘gnus-button-mid-or-mail-heuristic’.
 
 ‘gnus-article-button-face’
      Face used on buttons.
 
 ‘gnus-article-mouse-face’
      Face used when the mouse cursor is over a button.
 
    Customizing Articles, for how to buttonize articles
 automatically.
 

Info Catalog gnus: Article Header gnus: Article Treatment gnus: Article Button Levels