Info Catalog elisp: Predicates on Markers elisp: Markers elisp: Information from Markers

elisp: Creating Markers

 
 30.3 Functions that Create Markers
 ==================================
 
 When you create a new marker, you can make it point nowhere, or point to
 the present position of point, or to the beginning or end of the
 accessible portion of the buffer, or to the same place as another given
 marker.
 
    The next four functions all return markers with insertion type ‘nil’.
 Marker Insertion Types.
 
  -- Function: make-marker
      This function returns a newly created marker that does not point
      anywhere.
 
           (make-marker)
                ⇒ #<marker in no buffer>
 
  -- Function: point-marker
      This function returns a new marker that points to the present
      position of point in the current buffer.  Point.  For an
      example, see ‘copy-marker’, below.
 
  -- Function: point-min-marker
      This function returns a new marker that points to the beginning of
      the accessible portion of the buffer.  This will be the beginning
      of the buffer unless narrowing is in effect.  Narrowing.
 
  -- Function: point-max-marker
      This function returns a new marker that points to the end of the
      accessible portion of the buffer.  This will be the end of the
      buffer unless narrowing is in effect.  Narrowing.
 
      Here are examples of this function and ‘point-min-marker’, shown in
      a buffer containing a version of the source file for the text of
      this chapter.
 
           (point-min-marker)
                ⇒ #<marker at 1 in markers.texi>
           (point-max-marker)
                ⇒ #<marker at 24080 in markers.texi>
 
           (narrow-to-region 100 200)
                ⇒ nil
           (point-min-marker)
                ⇒ #<marker at 100 in markers.texi>
           (point-max-marker)
                ⇒ #<marker at 200 in markers.texi>
 
  -- Function: copy-marker &optional marker-or-integer insertion-type
      If passed a marker as its argument, ‘copy-marker’ returns a new
      marker that points to the same place and the same buffer as does
      MARKER-OR-INTEGER.  If passed an integer as its argument,
      ‘copy-marker’ returns a new marker that points to position
      MARKER-OR-INTEGER in the current buffer.
 
      The new marker’s insertion type is specified by the argument
      INSERTION-TYPE.  Marker Insertion Types.
 
           (copy-marker 0)
                ⇒ #<marker at 1 in markers.texi>
 
           (copy-marker 90000)
                ⇒ #<marker at 24080 in markers.texi>
 
      An error is signaled if MARKER is neither a marker nor an integer.
 
    Two distinct markers are considered ‘equal’ (even though not ‘eq’) to
 each other if they have the same position and buffer, or if they both
 point nowhere.
 
      (setq p (point-marker))
           ⇒ #<marker at 2139 in markers.texi>
 
      (setq q (copy-marker p))
           ⇒ #<marker at 2139 in markers.texi>
 
      (eq p q)
           ⇒ nil
 
      (equal p q)
           ⇒ t
 

Info Catalog elisp: Predicates on Markers elisp: Markers elisp: Information from Markers