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ccmode: Hungry WS Deletion

 
 4.8 Hungry Deletion of Whitespace
 =================================
 
 If you want to delete an entire block of whitespace at point, you can
 use “hungry deletion”.  This deletes all the contiguous whitespace
 either before point or after point in a single operation.  “Whitespace”
 here includes tabs and newlines, but not comments or preprocessor
 commands.  Hungry deletion can markedly cut down on the number of times
 you have to hit deletion keys when, for example, you’ve made a mistake
 on the preceding line and have already pressed ‘C-j’.
 
    Hungry deletion is a simple feature that some people find extremely
 useful.  In fact, you might find yourself wanting it in *all* your
 editing modes!
 
    Loosely speaking, in what follows, “<DEL>” means “the backspace key”
 and “<DELETE>” means “the forward delete key”.  This is discussed in
 more detail below.
 
    There are two different ways you can use hungry deletion:
 
 Using “Hungry Delete Mode” with ‘<DEL>’ and ‘C-d’
      Here you toggle Hungry Delete minor mode with ‘M-x
      c-toggle-hungry-state’(1) (Minor Modes.)  This makes
      ‘<DEL>’ and ‘C-d’ do backwards and forward hungry deletion.
 
      ‘<DEL>’ (‘c-electric-backspace’)
           This command is run by default when you hit the ‘DEL’ key.
           When hungry delete mode is enabled, it deletes any amount of
           whitespace in the backwards direction.  Otherwise, or when
           used with a prefix argument or in a literal (
           Auto-newlines), the command just deletes backwards in the
           usual way.  (More precisely, it calls the function contained
           in the variable ‘c-backspace-function’, passing it the prefix
           argument, if any.)
 
      ‘c-backspace-function’
           Hook that gets called by ‘c-electric-backspace’ when it
           doesn’t do an “electric” deletion of the preceding whitespace.
           The default value is ‘backward-delete-char-untabify’ (
           (elisp)Deletion, the function which deletes a single
           character.
 
      ‘C-d’ (‘c-electric-delete-forward’)
           This function, which is bound to ‘C-d’ by default, works just
           like ‘c-electric-backspace’ but in the forward direction.
           When it doesn’t do an “electric” deletion of the following
           whitespace, it just does ‘delete-char’, more or less.
           (Strictly speaking, it calls the function in
           ‘c-delete-function’ with the prefix argument.)
 
      ‘c-delete-function’
           Hook that gets called by ‘c-electric-delete-forward’ when it
           doesn’t do an “electric” deletion of the following whitespace.
           The default value is ‘delete-char’.
 
 Using Distinct Bindings
      The other (newer and recommended) way to use hungry deletion is to
      perform ‘c-hungry-delete-backwards’ and ‘c-hungry-delete-forward’
      directly through their key sequences rather than using the minor
      mode toggling.
 
      ‘C-c C-<DEL>’, or ‘C-c <DEL>’ (‘c-hungry-delete-backwards’)(2)
           Delete any amount of whitespace in the backwards direction
           (regardless whether hungry-delete mode is enabled or not).
           This command is bound to both ‘C-c C-<DEL>’ and ‘C-c <DEL>’,
           since the more natural one, ‘C-c C-<DEL>’, is sometimes
           difficult to type at a character terminal.
 
      ‘C-c C-d’, ‘C-c C-<DELETE>’, or ‘C-c <DELETE>’ (‘c-hungry-delete-forward’)
           Delete any amount of whitespace in the forward direction
           (regardless whether hungry-delete mode is enabled or not).
           This command is bound to both ‘C-c C-<DELETE>’ and ‘C-c
           <DELETE>’ for the same reason as for <DEL> above.
 
    When we talk about ‘<DEL>’, and ‘<DELETE>’ above, we actually do so
 without connecting them to the physical keys commonly known as
 <Backspace> and <Delete>.  The default bindings to those two keys
 depends on the flavor of (X)Emacs you are using.
 
    In XEmacs 20.3 and beyond, the <Backspace> key is bound to
 ‘c-electric-backspace’ and the <Delete> key is bound to
 ‘c-electric-delete’.  You control the direction it deletes in by setting
 the variable ‘delete-key-deletes-forward’, a standard XEmacs variable.
 When this variable is non-‘nil’, ‘c-electric-delete’ will do forward
 deletion with ‘c-electric-delete-forward’, otherwise it does backward
 deletion with ‘c-electric-backspace’.  Similarly, ‘C-c <Delete>’ and
 ‘C-c C-<Delete>’ are bound to ‘c-hungry-delete’ which is controlled in
 the same way by ‘delete-key-deletes-forward’.
 
    Emacs 21 and later automatically binds <Backspace> and <Delete> to
 ‘DEL’ and ‘C-d’ according to your environment, and CC Mode extends those
 bindings to ‘C-c C-<Backspace>’ etc.  If you need to change the bindings
 through ‘normal-erase-is-backspace-mode’ then CC Mode will also adapt
 its extended bindings accordingly.
 
    In earlier (X)Emacs versions, CC Mode doesn’t bind either <Backspace>
 or <Delete> directly.  Only the key codes ‘DEL’ and ‘C-d’ are bound, and
 it’s up to the default bindings to map the physical keys to them.  You
 might need to modify this yourself if the defaults are unsuitable.
 
    Getting your <Backspace> and <Delete> keys properly set up can
 sometimes be tricky.  The information in (emacs)DEL Does Not
 Delete, might be helpful if you’re having trouble with this in GNU
 Emacs.
 
    ---------- Footnotes ----------
 
    (1) Prior to CC Mode 5.31, this command was bound to ‘C-c C-d’.  ‘C-c
 C-d’ is now the default binding for ‘c-hungry-delete-forward’.
 
    (2) This command was formerly known as ‘c-hungry-backspace’.
 

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