Info Catalog elisp: Frames elisp: Top elisp: Markers

elisp: Positions

 
 29 Positions
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 A “position” is the index of a character in the text of a buffer.  More
 precisely, a position identifies the place between two characters (or
 before the first character, or after the last character), so we can
 speak of the character before or after a given position.  However, we
 often speak of the character “at” a position, meaning the character
 after that position.
 
    Positions are usually represented as integers starting from 1, but
 can also be represented as “markers”—special objects that relocate
 automatically when text is inserted or deleted so they stay with the
 surrounding characters.  Functions that expect an argument to be a
 position (an integer), but accept a marker as a substitute, normally
 ignore which buffer the marker points into; they convert the marker to
 an integer, and use that integer, exactly as if you had passed the
 integer as the argument, even if the marker points to the wrong buffer.
 A marker that points nowhere cannot convert to an integer; using it
 instead of an integer causes an error.  Markers.
 
    See also the field feature (Fields), which provides functions
 that are used by many cursor-motion commands.
 

Menu

 
· Point         The special position where editing takes place.
· Motion        Changing point.
· Excursions    Temporary motion and buffer changes.
· Narrowing     Restricting editing to a portion of the buffer.
 

Info Catalog elisp: Frames elisp: Top elisp: Markers