Homepage: https://www.gnu.org/software/emacs
Author: Dan Nicolaescu, Thien-Thi Nguyen
Minor mode cmds to selectively display code/comment blocks
* Commands provided
This file provides Hideshow Minor Mode. When active, nine commands
are available, implementing block hiding and showing. They (and their
keybindings) are:
hs-hide-block C-c @ C-h
hs-show-block C-c @ C-s
hs-hide-all C-c @ C-M-h
hs-show-all C-c @ C-M-s
hs-hide-level C-c @ C-l
hs-toggle-hiding C-c @ C-c
hs-toggle-hiding [(shift mouse-2)]
hs-hide-initial-comment-block
Blocks are defined per mode. In c-mode, c++-mode and java-mode, they
are simply text between curly braces, while in Lisp-ish modes parens
are used. Multi-line comment blocks can also be hidden. Read-only
buffers are not a problem, since hideshow doesn't modify the text.
The command `M-x hs-minor-mode' toggles the minor mode or sets it
(similar to other minor modes).
* Suggested usage
First make sure hideshow.el is in a directory in your `load-path'.
You can optionally byte-compile it using `M-x byte-compile-file'.
Then, add the following to your init file:
(load-library "hideshow")
(add-hook 'X-mode-hook #'hs-minor-mode) ; other modes similarly
where X = {emacs-lisp,c,c++,perl,...}. You can also manually toggle
hideshow minor mode by typing `M-x hs-minor-mode'. After hideshow is
activated or deactivated, `hs-minor-mode-hook' is run w/ `run-hooks'.
Additionally, Joseph Eydelnant writes:
I enjoy your package hideshow.el Version 5.24 2001/02/13
a lot and I've been looking for the following functionality:
toggle hide/show all with a single key.
Here are a few lines of code that lets me do just that.
(defvar my-hs-hide nil "Current state of hideshow for toggling all.")
;;;###autoload
(defun my-toggle-hideshow-all () "Toggle hideshow all."
(interactive)
(setq my-hs-hide (not my-hs-hide))
(if my-hs-hide
(hs-hide-all)
(hs-show-all)))
[Your hideshow hacks here!]
* Customization
You can use `M-x customize-variable' on the following variables:
- hs-hide-comments-when-hiding-all -- self-explanatory!
- hs-hide-all-non-comment-function -- if non-nil, when doing a
`hs-hide-all', this function
is called w/ no arguments
- hs-isearch-open -- what kind of hidden blocks to
open when doing isearch
Some languages (e.g., Java) are deeply nested, so the normal behavior
of `hs-hide-all' (hiding all but top-level blocks) results in very
little information shown, which is not very useful. You can use the
variable `hs-hide-all-non-comment-function' to implement your idea of
what is more useful. For example, the following code shows the next
nested level in addition to the top-level:
(defun ttn-hs-hide-level-1 ()
(when (hs-looking-at-block-start-p)
(hs-hide-level 1))
(forward-sexp 1))
(setq hs-hide-all-non-comment-function 'ttn-hs-hide-level-1)
Hideshow works w/ incremental search (isearch) by setting the variable
`hs-headline', which is the line of text at the beginning of a hidden
block that contains a match for the search. You can have this show up
in the mode line by modifying the variable `mode-line-format'. For
example, the following code prepends this info to the mode line:
(unless (memq 'hs-headline mode-line-format)
(setq mode-line-format
(append '("-" hs-headline) mode-line-format)))
See documentation for `mode-line-format' for more info.
Hooks are run after some commands:
hs-hide-hook in hs-hide-block, hs-hide-all, hs-hide-level
hs-show-hook hs-show-block, hs-show-all
One of `hs-hide-hook' or `hs-show-hook' is run for the toggling
commands when the result of the toggle is to hide or show blocks,
respectively. All hooks are run w/ `run-hooks'. See docs for each
variable or hook for more info.
Normally, hideshow tries to determine appropriate values for block
and comment definitions by examining the buffer's major mode. If
there are problems, hideshow will not activate and in that case you
may wish to override hideshow's heuristics by adding an entry to
variable `hs-special-modes-alist'. Packages that use hideshow should
do something like:
(add-to-list 'hs-special-modes-alist '(my-mode "{{" "}}" ...))
If you have an entry that works particularly well, consider
submitting it for inclusion in hideshow.el. See docstring for
`hs-special-modes-alist' for more info on the entry format.
See also variable `hs-set-up-overlay' for per-block customization of
appearance or other effects associated with overlays. For example:
(setq hs-set-up-overlay
(defun my-display-code-line-counts (ov)
(when (eq 'code (overlay-get ov 'hs))
(overlay-put ov 'display
(propertize
(format " ... <%d>"
(count-lines (overlay-start ov)
(overlay-end ov)))
'face 'font-lock-type-face)))))
* Bugs
(1) Sometimes `hs-headline' can become out of sync. To reset, type
`M-x hs-minor-mode' twice (that is, deactivate then re-activate
hideshow).
(2) Some buffers can't be `byte-compile-file'd properly. This is because
`byte-compile-file' inserts the file to be compiled in a temporary
buffer and switches `normal-mode' on. In the case where you have
`hs-hide-initial-comment-block' in `hs-minor-mode-hook', the hiding of
the initial comment sometimes hides parts of the first statement (seems
to be only in `normal-mode'), so there are unbalanced "(" and ")".
The workaround is to clear `hs-minor-mode-hook' when byte-compiling:
(defadvice byte-compile-file (around
byte-compile-file-hideshow-off
act)
(let ((hs-minor-mode-hook nil))
ad-do-it))
(3) Hideshow interacts badly with Ediff and `vc-diff'. At the moment, the
suggested workaround is to turn off hideshow entirely, for example:
(add-hook 'ediff-prepare-buffer-hook #'turn-off-hideshow)
(add-hook 'vc-before-checkin-hook #'turn-off-hideshow)
In the case of `vc-diff', here is a less invasive workaround:
(add-hook 'vc-before-checkin-hook
(lambda ()
(goto-char (point-min))
(hs-show-block)))
Unfortunately, these workarounds do not restore hideshow state.
If someone figures out a better way, please let me know.
* Correspondence
Correspondence welcome; please indicate version number. Send bug
reports and inquiries to .
* Thanks
Thanks go to the following people for valuable ideas, code and
bug reports.
Dean Andrews, Alf-Ivar Holm, Holger Bauer, Christoph Conrad, Dave Love,
Dirk Herrmann, Gael Marziou, Jan Djarv, Guillaume Leray, Moody Ahmad,
Preston F. Crow, Lars Lindberg, Reto Zimmermann, Keith Sheffield,
Chew Meng Kuan, Tony Lam, Pete Ware, François Pinard, Stefan Monnier,
Joseph Eydelnant, Michael Ernst, Peter Heslin
Special thanks go to Dan Nicolaescu, who reimplemented hideshow using
overlays (rather than selective display), added isearch magic, folded
in custom.el compatibility, generalized comment handling, incorporated
mouse support, and maintained the code in general. Version 4.0 is
largely due to his efforts.
* History
Hideshow was inspired when I learned about selective display. It was
reimplemented to use overlays for 4.0 (see above). WRT older history,
entries in the masterfile corresponding to versions 1.x and 2.x have
been lost. XEmacs support is reliable as of 4.29. State save and
restore was added in 3.5 (not widely distributed), and reliable as of
4.30. Otherwise, the code seems stable. Passes checkdoc as of 4.32.
Version 5.x uses new algorithms for block selection and traversal,
unbundles state save and restore, and includes more isearch support.