#+TITLE:   ui/popup
#+DATE:    January 6, 2018
#+SINCE:   v2.0.9
#+STARTUP: inlineimages

* Table of Contents :TOC:
- [[#description][Description]]
  - [[#module-flags][Module Flags]]
- [[#prerequisites][Prerequisites]]
- [[#configuration][Configuration]]
  - [[#set-popup-rule-and-set-popup-rules][~set-popup-rule!~ and ~set-popup-rules!~]]
  - [[#disabling-hidden-mode-line-in-popups][Disabling hidden mode-line in popups]]
- [[#appendix][Appendix]]
  - [[#commands][Commands]]
  - [[#library][Library]]
  - [[#hacks][Hacks]]

* Description
This module provides a customizable popup window management system.

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 the second class citizens of my editor;
spawned off to the side, discarded with the push of a button (e.g. =ESC= or
=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.

** Module Flags
+ =+all= Enables fallback rules to ensure all temporary/special buffers (whose
  name begins with a space or asterix) are treated as popups.
+ =+defaults= Enables reasonable default popup rules for a variety of buffers.

* Prerequisites
This module has no external prerequisites.

* Configuration
** ~set-popup-rule!~ and ~set-popup-rules!~
This module has two functions for defining your own rules for popups:

#+BEGIN_SRC emacs-lisp
(set-popup-rule! PREDICATE &key IGNORE ACTIONS SIDE SIZE WIDTH HEIGHT SLOT VSLOT TTL QUIT SELECT MODELINE AUTOSAVE PARAMETERS)
(set-popup-rules! &rest RULESETS)
#+END_SRC

~PREDICATE~ is a predicate function or regexp string to match against the
buffer's name. You'll find comprehensive documentation on the other keywords in
~set-popup-rule!~'s docstring (=SPC h f set-popup-rule!=).

#+begin_quote
Popup rules end up in ~display-buffer-alist~, which instructs ~display-buffer~
calls on how to set up windows for buffers that meet certain conditions.
However, some plugins can avoid it entirely if they use ~set-buffer~ or
~switch-to-buffer~, which don't obey ~display-buffer-alist~.
#+end_quote

Multiple popup rules can be defined with ~set-popup-rules!~:

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

Omitted parameters in a ~set-popup-rules!~ will use the defaults set in
~+popup-defaults~.

** Disabling hidden mode-line in popups
By default, the mode-line is hidden in popups. To disable this, you can either:

1. Change the default ~:modeline~ property in ~+popup-defaults~:

   #+BEGIN_SRC emacs-lisp
   ;; add to $DOOMDIR/config.el
   (plist-put +popup-defaults :modeline t)
   #+END_SRC

   A value of ~t~ will instruct popups to use the default mode-line. Any
   popup rule with a ~:modeline~ property can still override this.

2. Completely disable management of the mode-line in popups:

   #+BEGIN_SRC emacs-lisp
   ;; add to ~/.doom.d/config.el
   (remove-hook '+popup-buffer-mode-hook #'+popup-set-modeline-on-enable-h)
   #+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-h~
  + ~+popup|set-modeline~
  + ~+popup-close-on-escape-h~
  + ~+popup-cleanup-rules-h~
+ 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 restore 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~. Some work has gone into reversing this.