NOTE (2016-02-19): Maintaining this package turned out to be more of a pain than expected due to a multitude of edge-cases caused by other functions and modes that assume that an end-of-file overlay is empty (or at least constant in size). Sadly, I could never find the time or motivation to put that much work into getting this package to play nicely with others, so development has ceased.
Vim-like empty line indicator at end of files for Emacs.
This mode emulates the way that vim indicates the end of a file,
that is by putting a "tilde" character (~
) on any empty line that
follows the end of file.
Emacs provides a similar functionality that inserts a bitmap in the
fringe on the extraneous lines. By customizing
indicate-empty-lines
and fringe-indicator-alist
it is possible
to nearly emulate the vim behaviour.
However, there is a slight difference in what the two editors consider to be "empty lines".
A line in vim can be considered to contain the newline character that ended the previous line, as well as the other visible characters. Equivalently, a line is empty only if it contains no text and the previous line has no trailing whitespace.
Example:
foo <- not empty
\nbar <- not empty
\n <- not empty
~ <- empty
~ <- empty
foo <- not empty
\nbar <- not empty
~ <- empty
~ <- empty
A line in emacs, on the other hand, will contain the newline character that breaks it. Thus a line is empty even if the previous line has a trailing linebreak.
Example:
foo\n <- not empty
bar\n <- not empty
~ <- empty
~ <- empty
foo\n <- not empty
bar <- not empty
~ <- empty
~ <- empty
Note that Emacs displays the two cases identically!
There is currently (as of Emacs 24.4) no way to implement the
vim-like behaviour for indicate-empty-lines
short of modifying
the Emacs core.
This module emulates the vim-like behaviour using a different approach, namely by inserting at the end of the buffer a read-only overlay containing the indicators for the empty lines. This has the added advantage that it's trivial to customize the indicator to an arbitrary string, and customize its text properties.
To enable `vim-empty-lines-mode' in a buffer, run
(vim-empty-lines-mode)
To enable it globally, run
(global-vim-empty-lines-mode)
To automatically enable it only for certain buffers, set it to run within a hook. For example, to enable it only for programming modes, run
(add-hook 'prog-mode-hook 'vim-empty-lines-mode)
You can also choose to selectively disable it for certain modes. If it is initialized with
(global-vim-empty-lines-mode)
(add-hook 'text-mode-hook (lambda () (vim-empty-lines-mode -1)))
it will be enabled in all modes except those derived from text-mode
.
The string that indicates an empty line can be customized, e.g.
(setq vim-empty-lines-indicator "**********************")
The face that is used to display the indicators is vim-empty-lines-face
.