modules/buffer: add read buffer

modules/buffer.nix

@@ -1,39 +1,58 @@
 { config, lib, ... }:
 
 let
+  cfg = config.buffer;
+
   options = import ./vim/options.nix { inherit lib; };
 
   bufferOpts = { name, config, ... }: {
     options = with lib; {
-      filetypes = mkOption {
+      pattern = mkOption {
         type = types.extCommas;
         description = "File types for which the buffer is enabled";
       };
       opt = options.buffer // options.window;
     };
     config = {
-      filetypes = lib.mkDefault name;
+      pattern = lib.mkIf (!lib.hasPrefix "[definition " name) (lib.mkDefault name);
     };
   };
 
-  mkFiletypeBuffer = name: cfg:
+  mkBuffer = { prefix, event }: name: cfg:
     lib.nameValuePair
-      "buffer-${name}"
+      "buffer-${prefix}-${name}"
       {
-        event = "FileType";
-        pattern = cfg.filetypes;
-        callback = with lib; with nix2lua; lambda ["ev"] (lib.flatten [
+        inherit event;
+        inherit (cfg) pattern;
+        callback = with lib; with nix2lua; lambda [ "ev" ] (lib.flatten [
           (flip mapAttrsToList cfg.opt (k: v: if v == null then null else set "vim.opt.${k}" v))
         ]);
       };
+
+  mkFiletypeBuffer = mkBuffer { prefix = "filetype"; event = "FileType"; };
+
+  mkReadBuffer = cfg:
+    mkBuffer
+      { prefix = "read"; event = [ "BufNewFile" "BufRead" ]; }
+      (builtins.hashString "sha1" cfg.patterns)
+      cfg;
 in
 {
-  options.buffer = lib.mkOption {
+  options.buffer = {
+    read = lib.mkOption {
+      type = with lib.types; listOf (submodule bufferOpts);
+      default = [ ];
+    };
+    filetype = lib.mkOption {
       type = with lib.types; attrsOf (submodule bufferOpts);
       default = { };
     };
+  };
 
   config = {
-    vim.augroup = lib.mkIf (config.buffer != {}) (lib.listToAttrs (lib.mapAttrsToList mkFiletypeBuffer config.buffer));
+    vim.augroup = lib.mkMerge [
+      (lib.mkIf (cfg.filetype != { }) (lib.listToAttrs (lib.mapAttrsToList mkFiletypeBuffer cfg.filetype)))
+      (lib.mkIf (cfg.read != [ ]) (lib.listToAttrs (lib.map mkReadBuffer cfg.read)))
+    ];
   };
 }