Info Catalog elisp: Deletion elisp: Text elisp: The Kill Ring

elisp: User-Level Deletion

 
 31.7 User-Level Deletion Commands
 =================================
 
 This section describes higher-level commands for deleting text, commands
 intended primarily for the user but useful also in Lisp programs.
 
  -- Command: delete-horizontal-space &optional backward-only
      This function deletes all spaces and tabs around point.  It returns
      ‘nil’.
 
      If BACKWARD-ONLY is non-‘nil’, the function deletes spaces and tabs
      before point, but not after point.
 
      In the following examples, we call ‘delete-horizontal-space’ four
      times, once on each line, with point between the second and third
      characters on the line each time.
 
           ---------- Buffer: foo ----------
           I ★thought
           I ★     thought
           We★ thought
           Yo★u thought
           ---------- Buffer: foo ----------
 
           (delete-horizontal-space)   ; Four times.
                ⇒ nil
 
           ---------- Buffer: foo ----------
           Ithought
           Ithought
           Wethought
           You thought
           ---------- Buffer: foo ----------
 
  -- Command: delete-indentation &optional join-following-p
      This function joins the line point is on to the previous line,
      deleting any whitespace at the join and in some cases replacing it
      with one space.  If JOIN-FOLLOWING-P is non-‘nil’,
      ‘delete-indentation’ joins this line to the following line instead.
      The function returns ‘nil’.
 
      If there is a fill prefix, and the second of the lines being joined
      starts with the prefix, then ‘delete-indentation’ deletes the fill
      prefix before joining the lines.  Margins.
 
      In the example below, point is located on the line starting
      ‘events’, and it makes no difference if there are trailing spaces
      in the preceding line.
 
           ---------- Buffer: foo ----------
           When in the course of human
           ★    events, it becomes necessary
           ---------- Buffer: foo ----------
 
           (delete-indentation)
                ⇒ nil
 
           ---------- Buffer: foo ----------
           When in the course of human★ events, it becomes necessary
           ---------- Buffer: foo ----------
 
      After the lines are joined, the function ‘fixup-whitespace’ is
      responsible for deciding whether to leave a space at the junction.
 
  -- Command: fixup-whitespace
      This function replaces all the horizontal whitespace surrounding
      point with either one space or no space, according to the context.
      It returns ‘nil’.
 
      At the beginning or end of a line, the appropriate amount of space
      is none.  Before a character with close parenthesis syntax, or
      after a character with open parenthesis or expression-prefix
      syntax, no space is also appropriate.  Otherwise, one space is
      appropriate.  Syntax Class Table.
 
      In the example below, ‘fixup-whitespace’ is called the first time
      with point before the word ‘spaces’ in the first line.  For the
      second invocation, point is directly after the ‘(’.
 
           ---------- Buffer: foo ----------
           This has too many     ★spaces
           This has too many spaces at the start of (★   this list)
           ---------- Buffer: foo ----------
 
           (fixup-whitespace)
                ⇒ nil
           (fixup-whitespace)
                ⇒ nil
 
           ---------- Buffer: foo ----------
           This has too many spaces
           This has too many spaces at the start of (this list)
           ---------- Buffer: foo ----------
 
  -- Command: just-one-space &optional n
      This command replaces any spaces and tabs around point with a
      single space, or N spaces if N is specified.  It returns ‘nil’.
 
  -- Command: delete-blank-lines
      This function deletes blank lines surrounding point.  If point is
      on a blank line with one or more blank lines before or after it,
      then all but one of them are deleted.  If point is on an isolated
      blank line, then it is deleted.  If point is on a nonblank line,
      the command deletes all blank lines immediately following it.
 
      A blank line is defined as a line containing only tabs and spaces.
 
      ‘delete-blank-lines’ returns ‘nil’.
 
  -- Command: delete-trailing-whitespace &optional start end
      Delete trailing whitespace in the region defined by START and END.
 
      This command deletes whitespace characters after the last
      non-whitespace character in each line in the region.
 
      If this command acts on the entire buffer (i.e., if called
      interactively with the mark inactive, or called from Lisp with END
      ‘nil’), it also deletes all trailing lines at the end of the buffer
      if the variable ‘delete-trailing-lines’ is non-‘nil’.
 

Info Catalog elisp: Deletion elisp: Text elisp: The Kill Ring