Add new dir argument to simplify fonts with many files

flake.nix

@@ -22,8 +22,13 @@
             sLen = stringLength str;
           in sufLen <= sLen && suffix == substring (sLen - sufLen) sufLen str;
 
-        buildFont = { name, files, license, author, }:
+        buildFont = { name, files ? [ ], dir ? null, license, author }:
           let
+            types = {
+              ttf = "truetype";
+              otf = "opentype";
+            };
+
             copyType = extension: pathName:
               let
                 filteredFiles = filter (pathEndsWith ("." + extension)) files;
@@ -34,14 +39,19 @@
               '') + concatStringsSep "\n" (map (file:
                 "cp -v ${file} $out/share/fonts/${pathName}/${filename file}")
                 filteredFiles);
+
+            copyTypeDir = extension: pathName: ''
+              if [ -n "$(shopt -s nullglob; echo ${dir}/*.${extension})" ]; then
+                mkdir -p $out/share/fonts/${pathName}
+                cp -v -t $out/share/fonts/${pathName} ${dir}/*.${extension}
+              fi
+            '';
           in pkgs.stdenvNoCC.mkDerivation {
             inherit name;
 
             dontUnpack = true;
-            installPhase = ''
-              ${copyType "ttf" "truetype"}
-              ${copyType "otf" "opentype"}
-            '';
+            installPhase = mapAttrsToList copyType types
+              ++ optional (dir != null) (mapAttrsToList copyTypeDir types);
 
             meta = {
               inherit license;
@@ -59,8 +69,7 @@
           }
           {
             name = "gg sans";
-            files =
-              [ ./ggsans/ggsans-Normal.ttf ./ggsans/ggsans-Medium.ttf ./ggsans/ggsans-SemiBold.ttf ];
+            dir = ./ggsans;
             license = licenses.unfree;
             author = "Colophon Foundry";
           }