EMACS added ligatures package for prog mode

Signed-off-by: Stefan Ellmauthaler <stefan.ellmauthaler@tu-dresden.de>

programs/emacs/default.el

@@ -559,6 +559,20 @@
   :commands
   (academic-phrases
    academic-phrases-by-section))
+
+(use-package ligature
+  :config
+  (ligature-set-ligatures 'prog-mode
+                          '("&&" "***" "*>" "\\\\" "||" "|>" "::"
+                            "==" "===" "==>" "=>" "=<<" "!!" ">>"
+                            ">>=" ">>>" ">>-" ">-" "->" "-<" "-<<"
+                            "<*" "<*>" "<|" "<|>" "<$>" "<>" "<-"
+                                        ; disable ++ until > emacs-27.2, since C++-mode causes a crash otherwise
+                                        ;                            "<<" "<<<" "<+>" ".." "..." "++" "+++"
+                            "<<" "<<<" "<+>" ".." "..." "+++"
+                            "/=" ":::" ">=>" "->>" "<=>" "<=<" "<->"))
+  (global-ligature-mode t))
+
 (custom-set-faces
  ;; custom-set-faces was added by Custom.
  ;; If you edit it by hand, you could mess it up, so be careful.

programs/emacs/default.nix

@@ -84,7 +84,10 @@ let
         yaml-mode
         yasnippet
         #zenburn-theme
-      ] ++ (with lpkgs; [org-roam-ui])));
+      ] ++ (with lpkgs; [
+        org-roam-ui
+        ligatures
+      ])));
 in
 {
   services.emacs = {

programs/emacs/packages.nix

@@ -16,4 +16,15 @@ with epkgs; rec{
       cp -r out $out/share/emacs/site-lisp
     '';  
   };
+
+  ligatures = trivialBuild {
+    pname = "ligatures";
+    version = "unstable-2021-08-27";
+    src = pkgs.fetchFromGitHub {
+      owner = "mickeynp";
+      repo = "ligature.el";
+      rev = "d3426509cc5436a12484d91e48abd7b62429b7ef";
+      sha256 = "baFDkfQLM2MYW2QhMpPnOMSfsLlcp9fO5xfyioZzOqg=";
+    };
+  };
 }