Leo wrote:
> On 2007-10-28 14:20 +0000, Vinicius Jose Latorre wrote:
>   
>> Hi,
>>
>> It seems there is an interest to install blank-mode package in the
>> Emacs distribution.
>>     
> [...]
>
> There is another package whitespace.el included in Emacs already that
> seems to do similar things.
>   

whitespace.el is different from blank-mode:

;; The whitespace library is intended to find and help fix five 
different types
;; of whitespace problems that commonly exist in source code.
;;
;; 1. Leading space (empty lines at the top of a file).
;; 2. Trailing space (empty lines at the end of a file).
;; 3. Indentation space (8 or more spaces at beginning of line, that 
should be
;;              replaced with TABS).
;; 4. Spaces followed by a TAB.  (Almost always, we never want that).
;; 5. Spaces or TABS at the end of a line.
;;
;; Whitespace errors are reported in a buffer, and on the modeline.

Also, whitespace uses text properties to highlight and blank-mode uses 
font-lock and/or display table.

The whitespace purpose is to detect problems and blank-mode purpose is 
only to visualise any space.  That is, whitespace only highlight spaces 
when there is a problem.

The attached image shows when blank-mode is on.