Add Nix config

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "chatgpt-shell"]
-	path = chatgpt-shell
-	url = https://github.com/xenodium/chatgpt-shell

chatgpt-shell

@@ -1 +0,0 @@
-Subproject commit f7a53903ebedb1bd67dc9dea6ae9893fb70d4d49

config.org

@@ -119,7 +119,7 @@
    #+begin_src emacs-lisp
      (let ((font-height
             (pcase hostname
-              ("eagle" 100)
+              ("zora" 100)
               ("eddie" 100)
               ("mandarax" 115)
               ("valis" 80)
@@ -609,11 +609,10 @@
      (setq-default basic-offset 4)
    #+end_src
 
-   And generally indenting with spaces is more common, so make that
-   the default:
+   Use tabs as god intended:
 
    #+begin_src emacs-lisp
-     (setq-default indent-tabs-mode nil)
+     (setq-default indent-tabs-mode t)
    #+end_src
 
 *** Language Server Protocol
@@ -674,15 +673,7 @@
     #+end_src
 
 ** C
-    For C there is =clangd= implementing LSP. Assuming that's
-    installed and on the =PATH=, we can just hook =lsp-mode= into the
-    default mode and there will be much rejoicing.
-
-    #+begin_src emacs-lisp
-      (add-hook 'c-mode-hook #'lsp-deferred)
-    #+end_src
-
-    As for indenting style, I like BSD-style but with 4-char-wide indents
+    For indenting style, I like BSD-style but with 4-char-wide indents
 
     #+begin_src emacs-lisp
       (add-hook 'c-mode-hook (lambda ()
@@ -699,8 +690,7 @@
     There's a lot of boilerplate in C, so I want YASnippet enabled.
 
     #+begin_src emacs-lisp
-      (add-hook 'c-mode-hook (lambda ()
-                               (yas-minor-mode)))
+	  (add-hook 'c-mode-hook (lambda () (yas-minor-mode)))
     #+end_src
 
 ** C++
@@ -929,26 +919,6 @@
      (add-to-list 'auto-mode-alist '("\\.pl\\'" . prolog-mode))
    #+end_src
 
-** Java
-   [[https://github.com/jdee-emacs/jdee][JDEE]] provides a whole bunch of tooling for Java. It requires the
-   [[https://github.com/jdee-emacs/jdee-server][JDEE server]] to work properly, which has to be built seperately
-   (this requires JDK and Maven):
-
-   #+begin_src shell :tangle no
-     cd ~/src
-     git clone https://github.com/jdee-emacs/jdee-server.git
-     cd jdee-server
-     mvn -Dmaven.test.skip=true package
-   #+end_src
-
-   With that built, we can install JDEE, pointing at the built server:
-
-   #+begin_src emacs-lisp
-     (use-package jdee
-       :config
-       (setq jdee-server-dir "~/src/jdee-server/target"))
-   #+end_src
-
 ** Dockerfiles
    Grab =dockerfile-mode= for syntax highlighting etc in Dockerfiles:
 
@@ -1048,22 +1018,6 @@
      (add-hook 'python-mode-hook #'lsp-deferred)
    #+end_src
 
-** C#
-   I hate the .NET ecosystem quite a lot, but alas: sometimes I have
-   to use it at work.
-
-   Using =csharp-mode= for basic support:
-
-   #+begin_src emacs-lisp
-     (use-package csharp-mode)
-   #+end_src
-
-   And =lsp-mode= for the rest (using the omnisharp server):
-
-   #+begin_src emacs-lisp
-     (add-hook 'csharp-mode-hook #'lsp-deferred)
-   #+end_src
-
 ** Ada
 *** Old ada-mode
     Unfortunately, the =ada-mode= on ELPA is hot garbage. It requires
@@ -1224,11 +1178,69 @@
      #+end_src
 
 ** Lua
-   Using a pretty standard LSP setup for Lua:
+   Just using basic =lua-mode= package:
 
    #+begin_src emacs-lisp
      (use-package lua-mode)
-     (add-hook 'lua-mode-hook #'lsp-deferred)
+   #+end_src
+
+   I want to indent with tabs (set to 4 characters wide):
+
+   #+begin_src emacs-lisp
+	 (setq lua-indent-level 4)
+   #+end_src
+
+   I also want to be able to run =lua-format= on files with =C-c f=
+   like I have with =clang-format=. The first step for this is to make
+   an interactive function to run the formatter; this can be done with
+   [[help:call-process-region][call-process-region]].
+
+   #+begin_src emacs-lisp
+	 (defvar lua-format-binary "lua-format")
+
+	 (defun lua-format ()
+	   (interactive)
+	   (if (executable-find lua-format-binary)
+		   (let ((start (if (region-active-p) (region-beginning) (point-min)))
+				 (end (if (region-active-p) (region-end) (point-max))))
+			 (call-process-region start end lua-format-binary t '(t nil)))
+		 (error "%s" (concat lua-format-binary " not found."))))
+   #+end_src
+
+   This then needs to be assigned to the keybinding:
+
+   #+begin_src emacs-lisp
+	 (add-hook
+	  'lua-mode-hook
+	  (lambda () (define-key lua-mode-map (kbd "C-c f") 'lua-format)))
+   #+end_src
+
+** BASIC
+   =basic-mode= provides syntax highlighting and a few nice features:
+
+   #+begin_src emacs-lisp
+	 (use-package basic-mode)
+   #+end_src
+
+   As well as =.bas= files, I want to open all =.bbc= files in
+   =basic-mode=:
+
+   #+begin_src emacs-lisp
+	 (add-to-list 'auto-mode-alist '("\\.bbc\\'" . basic-mode))
+   #+end_src
+
+** Nix
+   Basic editing support comes from =nix-mode=:
+
+   #+begin_src emacs-lisp
+	 (use-package nix-mode)
+   #+end_src
+
+   And =nix-update= provides a convenient way to update ~fetch~
+   blocks:
+
+   #+begin_src emacs-lisp
+	 (use-package nix-update)
    #+end_src
 
 * Tool Integrations
@@ -1341,14 +1353,11 @@
    #+end_src
 
 ** ChatGPT
-   The =chatpt-shell= package is in a git submodule, so this has to be
-   added to the [[help:load-path][load-path]] and ~require~'d:
+   The =chatpt-shell= package provides a shell-like interface for
+   ChatGPT.
 
    #+begin_src emacs-lisp
-     (let ((path (concat (getenv "HOME")
-                         "/.emacs.d/chatgpt-shell")))
-       (add-to-list 'load-path path))
-     (require 'chatgpt-shell)
+	 (use-package chatgpt-shell)
    #+end_src
 
    [[help:chatgpt-shell-openai-key][chatgpt-shell-openai-key]] must also be set to a function that
@@ -1530,6 +1539,14 @@
      (global-set-key (kbd "C-.") #'god-mode-all)
    #+end_src
 
+   I find it jarring and confusing to have it on and off in different
+   types of buffers, so will just disable the exemptions:
+
+   #+begin_src emacs-lisp
+     (setq god-exempt-major-modes nil)
+     (setq god-exempt-predicates nil)
+   #+end_src
+
 ** Case-flipping
    Want to be able to toggle the 'shiftedness' of a selected region,
    that is, map uppercase to lowercase and vice versa, but also map
@@ -1621,3 +1638,13 @@
    #+begin_src emacs-lisp
      (global-set-key (kbd "C-~") 'flip-region-case)
    #+end_src
+
+* Fin
+  Now that start-up is finished, [[help:gc-cons-threshold][gc-cons-threshold]] and
+  [[help:gc-cons-percentage][gc-cons-percentage]] need to be set back to reasonable values to avoid
+  memory usage getting too high.
+
+  #+begin_src emacs-lisp
+	(setq gc-cons-threshold 1000000)
+	(setq gc-cons-percentage 0.2)
+  #+end_src