feat(snippets/luasnip): allow custom snippets

docs/release-notes/rl-0.8.md

@@ -352,6 +352,7 @@
 
 [rrvsh](https://github.com/rrvsh):
 
+- Add custom snippet support to `vim.snippets.luasnip`
 - Fix namespace of python-lsp-server by changing it to python3Packages
 
 [Noah765](https://github.com/Noah765):

modules/plugins/snippets/luasnip/config.nix

@@ -1,11 +1,48 @@
 {
   config,
   lib,
+  pkgs,
   ...
 }: let
   inherit (lib.modules) mkIf;
 
+  inherit (lib.lists) replicate;
+  inherit
+    (lib.strings)
+    optionalString
+    removeSuffix
+    concatStrings
+    stringAsChars
+    concatMapStringsSep
+    ;
+  inherit (lib.attrsets) mapAttrsToList;
+  inherit (pkgs) writeTextFile;
   cfg = config.vim.snippets.luasnip;
+  # LuaSnip freaks out if the indentation is wrong in snippets
+  indent = n: s: let
+    indentString = concatStrings (replicate n " ");
+    sep = "\n" + indentString;
+  in
+    indentString
+    + stringAsChars (c:
+      if c == "\n"
+      then sep
+      else c) (removeSuffix "\n" s);
+  customSnipmateSnippetFiles =
+    mapAttrsToList (
+      name: value:
+        writeTextFile {
+          name = "${name}.snippets";
+          text =
+            concatMapStringsSep "\n" (x: ''
+              snippet ${x.trigger} ${x.description}
+              ${indent 2 x.body}
+            '')
+            value;
+          destination = "/snippets/${name}.snippets";
+        }
+    )
+    cfg.customSnippets.snipmate;
 in {
   config = mkIf cfg.enable {
     vim = {
@@ -19,11 +56,16 @@ in {
 
         after = cfg.loaders;
       };
-      startPlugins = cfg.providers;
+      startPlugins = cfg.providers ++ customSnipmateSnippetFiles;
       autocomplete.nvim-cmp = mkIf config.vim.autocomplete.nvim-cmp.enable {
         sources = {luasnip = "[LuaSnip]";};
         sourcePlugins = ["cmp-luasnip"];
       };
+      snippets.luasnip.loaders = ''
+        ${optionalString (
+          cfg.customSnippets.snipmate != {}
+        ) "require('luasnip.loaders.from_snipmate').lazy_load()"}
+      '';
     };
   };
 }

modules/plugins/snippets/luasnip/luasnip.nix

@@ -1,6 +1,6 @@
 {lib, ...}: let
   inherit (lib.options) mkEnableOption mkOption literalExpression literalMD;
-  inherit (lib.types) listOf lines;
+  inherit (lib.types) listOf lines submodule str attrsOf;
   inherit (lib.nvim.types) pluginType mkPluginSetupOption;
 in {
   options.vim.snippets.luasnip = {
@@ -36,5 +36,61 @@ in {
     setupOpts = mkPluginSetupOption "LuaSnip" {
       enable_autosnippets = mkEnableOption "autosnippets";
     };
+
+    customSnippets.snipmate = mkOption {
+      type = attrsOf (
+        listOf (submodule {
+          options = {
+            trigger = mkOption {
+              type = str;
+              description = ''
+                The trigger used to activate this snippet.
+              '';
+            };
+            description = mkOption {
+              type = str;
+              default = "";
+              description = ''
+                The description shown for this snippet.
+              '';
+            };
+            body = mkOption {
+              type = str;
+              description = ''
+                [LuaSnip Documentation]: https://github.com/L3MON4D3/LuaSnip#add-snippets
+                The body of the snippet in SnipMate format (see [LuaSnip Documentation]).
+              '';
+            };
+          };
+        })
+      );
+      default = {};
+      example = ''
+        {
+          all = [
+            {
+              trigger = "if";
+              body = "if $1 else $2";
+            }
+          ];
+          nix = [
+            {
+              trigger = "mkOption";
+              body = '''
+                mkOption {
+                  type = $1;
+                  default = $2;
+                  description = $3;
+                  example = $4;
+                }
+              ''';
+            }
+          ];
+        }
+      '';
+      description = ''
+        A list containing custom snippets in the SnipMate format to be loaded by LuaSnip.
+      '';
+    };
   };
 }