refactor(emacs-pkgs): Extract term-switcher into separate emacs pkg

2 files changed, 86 insertions, 0 deletions

diff --git a/tools/emacs-pkgs/term-switcher/default.nix b/tools/emacs-pkgs/term-switcher/default.nix
new file mode 100644
index 000000000000..ad96638a054c
--- /dev/null
+++ b/tools/emacs-pkgs/term-switcher/default.nix
@@ -0,0 +1,14 @@
+{ pkgs, ... }:
+
+with pkgs.third_party.emacsPackagesNg;
+
+melpaBuild rec {
+  pname = "term-switcher";
+  version = "1.0";
+  src = ./term-switcher.el;
+  packageRequires = [ dash ivy s ];
+
+  recipe = builtins.toFile "recipe" ''
+    (term-switcher :fetcher github :repo "tazjin/depot")
+  '';
+}
diff --git a/tools/emacs-pkgs/term-switcher/term-switcher.el b/tools/emacs-pkgs/term-switcher/term-switcher.el
new file mode 100644
index 000000000000..66247d68247c
--- /dev/null
+++ b/tools/emacs-pkgs/term-switcher/term-switcher.el
@@ -0,0 +1,72 @@
+;;; term-switcher.el --- Easily switch between open X11 terminals
+;;
+;; Copyright (C) 2019 Google Inc.
+;;
+;; Author: Vincent Ambo <tazjin@google.com>
+;; Version: 1.0
+;; Package-Requires: (dash ivy s)
+;;
+;;; Commentary:
+;;
+;; This package adds a function that lets users quickly switch between
+;; different open X11 terminals using ivy.
+;;
+;; It is primarily intended to be used by EXWM users who use graphical
+;; terminals inside of Emacs.
+;;
+;; Users MUST configure the group `term-switcher' and can then bind
+;; `ts/switch-to-terminal' to an appropriate key.
+
+(require 'dash)
+(require 'ivy)
+(require 's)
+
+(defgroup term-switcher nil
+  "Customization options for configuring `term-switcher' with the
+  user's terminal emulator of choice.")
+
+(defcustom term-switcher-program "gnome-terminal"
+  "X11 terminal application to use."
+  :type '(string)
+  :group 'term-switcher)
+
+(defcustom term-switcher-buffer-prefix "Term"
+  "String prefix for X11 terminal buffers. For example, if your
+  EXWM configuration renames X11 terminal buffers to
+  `Term</foo/bar>' you might want to use `Term' as the matching
+  prefix."
+  :type '(string)
+  :group 'term-switcher)
+
+(defun ts/run-terminal-program ()
+  (message "Starting %s..." term-switcher-program)
+  (start-process-shell-command term-switcher-program nil term-switcher-program))
+
+(defun ts/open-or-create-terminal-buffer (buffer-name)
+  "Switch to the buffer with BUFFER-NAME or create a new buffer
+  running the configured X11 terminal."
+  (let ((buffer (get-buffer buffer-name)))
+    (if (not buffer)
+        (ts/run-terminal-program)
+      (switch-to-buffer buffer))))
+
+(defun ts/is-terminal-buffer (buffer)
+  "Determine whether BUFFER runs an X11 terminal."
+  (and (equal 'exwm-mode (buffer-local-value 'major-mode buffer))
+       (s-starts-with? term-switcher-buffer-prefix (buffer-name buffer))))
+
+(defun ts/switch-to-terminal ()
+  "Switch to an X11 terminal buffer, or create a new one."
+  (interactive)
+  (let ((terms (-map #'buffer-name
+                     (-filter #'ts/is-terminal-buffer (buffer-list)))))
+    (if terms
+        (ivy-read "Switch to terminal buffer: "
+                  (cons "New terminal" terms)
+                  :caller 'ts/switch-to-terminal
+                  :preselect (s-concat "^" term-switcher-buffer-prefix)
+                  :require-match t
+                  :action #'ts/open-or-create-terminal-buffer)
+      (ts/run-terminal-program))))
+
+(provide 'term-switcher)