#+TITLE: :feature popup

This module provides a highly customizable popup window management system.

#+begin_quote
Not all windows are created equally. Some are less important. Some I want gone
once they have served their purpose, like code output or a help buffer. Others I
want to stick around, like a scratch buffer or org-capture popup.

More than that, popups ought to be be the second class citizens of my editor;
spawned off to the side, discarded with the simple push of a button
(Escape/C-g), and easily restored if I want to see them again. Of course, this
system should clean up after itself and kill off buffers I mark as transient.
#+end_quote

* Table of Contents :TOC:
- [[#configuration][Configuration]]
  - [[#the-popup-setting][The ~:popup~ setting]]
  - [[#disabling-aggressive-mode-line-hiding-in-popups][Disabling aggressive mode-line hiding in popups]]
- [[#appendix][Appendix]]
  - [[#commands][Commands]]
  - [[#library][Library]]
  - [[#hacks][Hacks]]

* Configuration
** The ~:popup~ setting
This module has one setting for defining your own rules for popups:

#+BEGIN_SRC emacs-lisp
(set! :popup CONDITION &optional ALIST PARAMETERS)
#+END_SRC

+ ~CONDITION~ can be a function or regexp string. If the function returns
  non-nil, or the regexp string matches the buffer's name, it will be opened in
  a popup window.
+ ~ALIST~ dictates the characteristics of the popup, such as what side to spawn
  it on and what size to make it. See ~display-buffer~'s documentation to see
  what parameters are supported.

  This supports one custom parameter: ~size~, which will map to ~window-width~
  or ~window-height~ depending on what ~side~ you (or the defaults) specify.
+ ~PARAMETERS~ dictate what window parameters are set on the popup window. See
  ~+popup-window-parameters~'s documentation and the [[https://www.gnu.org/software/emacs/manual/html_node/elisp/Window-Parameters.html#Window-Parameters][Window Parameters section
  of the Emacs manual]] for what parameters are supported.

  This supports four custom parameters: =transient=, =quit=, =select= and
  =modeline=. For details on these, look at the documentation for
  ~+popup-window-parameters.~

Rules are added to ~display-buffer-alist~, which instructs ~display-buffer~
calls on how to set up windows for buffers that meet certain conditions.

#+begin_quote
The ~switch-to-buffer~ command (and its ~switch-to-buffer-*~ variants) are not
affected by ~display-buffer-alist~.
#+end_quote

Here are a couple example rules:

#+BEGIN_SRC emacs-lisp
(set! :popup "^ \\*" '((slot . -1))) ; fallback rule for special buffers
(set! :popup "^\\*" nil '((select . t)))
(set! :popup "^\\*Completions" '((slot . -1)) '((transient . 0)))
(set! :popup "^\\*\\(?:scratch\\|Messages\\)" nil '((transient)))
(set! :popup "^\\*Help"
  '((slot . -1) (size . 0.2))
  '((select . t)))
(set! :popup "^\\*doom:"
  '((size . 0.35))
  '((select . t) (modeline . t) (quit) (transient)))
#+END_SRC

Omitted parameters in a ~:popup~ rule will use the defaults set in
~+popup-default-alist~ and ~+popup-default-parameters~.

** Disabling aggressive mode-line hiding in popups
There are two ways to go about this. You can turn on modelines by changing the
default ~'modeline~ window parameter in ~+popup-default-parameters~:

#+BEGIN_SRC emacs-lisp
;; put in private/$USER/config.el
(map-put +popup-default-parameters 'modeline t)
#+END_SRC

This will ensure all popups have a modeline /by default/, but allows you to override this on a per-popup basis.

*Alternatively*, you can disable modeline-hiding entirely:

#+BEGIN_SRC emacs-lisp
;; put in private/$USER/config.el
(remove-hook '+popup-buffer-mode-hook '+popup|set-modeline)
#+END_SRC

* Appendix
** Commands
+ ~+popup/other~ (aliased to ~other-popup~, bound to ~C-x p~)
+ ~+popup/toggle~
+ ~+popup/close~
+ ~+popup/close-all~
+ ~+popup/toggle~
+ ~+popup/restore~
+ ~+popup/raise~
** Library
+ Functions
  + ~+popup-window-p WINDOW~
  + ~+popup-buffer-p BUFFER~
  + ~+popup-buffer BUFFER &optional ALIST~
  + ~+popup-parameter PARAMETER &optional WINDOW~
  + ~+popup-parameter-fn PARAMETER &optional WINDOW~
  + ~+popup-windows~
+ Macros
  + ~without-popups!~
  + ~save-popups!~
+ Hooks
  + ~+popup|adjust-fringes~
  + ~+popup|set-modeline~
  + ~+popup|close-on-escape~
  + ~+popup|cleanup-rules~
+ Minor modes
  + ~+popup-mode~
  + ~+popup-buffer-mode~
** Hacks
+ =help-mode= has been advised to follow file links in the buffer you were in
  before entering the popup, rather than in a new window.
+ =wgrep= buffers are advised to close themselves when aborting or committing
  changes.
+ =persp-mode= is advised to restore popup windows when loading a session from
  file.
+ Interactive calls to ~windmove-*~ commands (used by ~evil-window-*~ commands)
  will ignore the ~no-other-window~ window parameter, allowing you to switch to
  popup windows as if they're ordinary windows.
+ ~balance-windows~ has been advised to close popups while it does its business,
  then restores them afterwards.
+ =neotree= advises ~balance-windows~, which causes major slow-downs when paired
  with our ~balance-window~ advice, so we removes neotree's advice.
+ =org-mode= is an ongoing (and huge) effort. It has a scorched-earth window
  management system I'm not fond of. ie. it kills all windows and monopolizes
  the frame. On top of that, it /really/ likes to use ~switch-to-buffer~ for
  most of its buffer management, which completely bypasses
  ~display-buffer-alist~.