Info Catalog ediff: Miscellaneous ediff: Customization

ediff: Notes on Heavy-duty Customization

 
 7.13 Notes on Heavy-duty Customization
 ======================================
 
 Some users need to customize Ediff in rather sophisticated ways, which
 requires different defaults for different kinds of files (e.g., SGML,
 etc.).  Ediff supports this kind of customization in several ways.
 First, most customization variables are buffer-local.  Those that aren’t
 are usually accessible from within Ediff Control Panel, so one can make
 them local to the panel by calling make-local-variable from within
 ‘ediff-startup-hook’.
 
    Second, the function ‘ediff-setup’ accepts an optional sixth argument
 which has the form ‘((VAR-NAME-1 . VAL-1) (VAR-NAME-2 . VAL-2) ...)’.
 The function ‘ediff-setup’ sets the variables in the list to the
 respective values, locally in the Ediff control buffer.  This is an easy
 way to throw in custom variables (which usually should be buffer-local)
 that can then be tested in various hooks.
 
    Make sure the variable ‘ediff-job-name’ and ‘ediff-word-mode’ are set
 properly in this case, as some things in Ediff depend on this.
 
    Finally, if you want custom-tailored help messages, you can set the
 variables ‘ediff-brief-help-message-function’ and
 ‘ediff-long-help-message-function’ to functions that return help
 strings.
 
    When customizing Ediff, some other variables are useful, although
 they are not user-definable.  They are local to the Ediff control
 buffer, so this buffer must be current when you access these variables.
 The control buffer is accessible via the variable
 ‘ediff-control-buffer’, which is also local to that buffer.  It is
 usually used for checking if the current buffer is also the control
 buffer.
 
    Other variables of interest are:
 ‘ediff-buffer-A’
      The first of the data buffers being compared.
 
 ‘ediff-buffer-B’
      The second of the data buffers being compared.
 
 ‘ediff-buffer-C’
      In three-way comparisons, this is the third buffer being compared.
      In merging, this is the merge buffer.  In two-way comparison, this
      variable is ‘nil’.
 
 ‘ediff-window-A’
      The window displaying buffer A.  If buffer A is not visible, this
      variable is ‘nil’ or it may be a dead window.
 
 ‘ediff-window-B’
      The window displaying buffer B.
 
 ‘ediff-window-C’
      The window displaying buffer C, if any.
 
 ‘ediff-control-frame’
      A dedicated frame displaying the control buffer, if it exists.  It
      is non-‘nil’ only if Ediff uses the multiframe display, i.e., when
      the control buffer is in its own frame.
 

Info Catalog ediff: Miscellaneous ediff: Customization