feat(emacs): configure plex in a package

modules/home/users/msyds/emacs.nix

@@ -19,6 +19,7 @@ in {
   imports = [
     ./emacs/nix/jinx.nix
     ./emacs/nix/tufte-latex.nix
+    ./emacs/nix/plex-latex.nix
   ];
 
   config = lib.mkIf cfg.enable {

modules/home/users/msyds/emacs/nix/plex-latex.nix

@@ -7,7 +7,33 @@ in {
   };
 
   config = lib.mkIf cfg.enable {
-    sydnix.emacs.tex.extraTexPackages = {
+    sydnix.emacs.tex.extraTexPackages =
+      let syd-plex = pkgs.stdenvNoCC.mkDerivation (final: {
+          pname = "syd-plex-latex";
+          version = "1.0.0";
+          src = ./plex-latex;
+          nativeBuildInputs = [ pkgs.texlive.combined.scheme-small ];
+          passthru = {
+            pkgs = [ final.finalPackage ];
+            tlDeps = with pkgs.texlive; [
+              plex
+              plex-otf
+              fontaxes
+              unicode-math
+              xetex
+            ];
+            tlType = "run";
+          };
+          installPhase = ''
+            runHook preInstall
+            dir="$out/tex/latex/syd-plex"
+            mkdir -p "$dir"
+            mv syd-plex.sty "$dir"
+            runHook postInstall
+          '';
+        });
+      in {
+        inherit syd-plex;
         inherit (pkgs.texlive)
           plex
           plex-otf

modules/home/users/msyds/emacs/nix/plex-latex/syd-plex.sty

@@ -0,0 +1,11 @@
+\NeedsTeXFormat{LaTeX2e}
+\ProvidesPackage{syd-plex}[2014/08/24 Configure IBM Plex fonts]
+Example LaTeX package
+
+% Redefine some commands to make unicode-math work lol.  See §3.1 of the
+% unicode-math manual.
+\renewcommand*{\mathrm}[1]{\symup{#1}}
+
+\RequirePackage{plex-otf}
+\setmathfont{IBM Plex Math}
+\setmainfont{IBM Plex Serif}