luasnip: init plugin (#56)

* luasnip: init plugin

Also added support for paths in `toLuaObject`

* luasnip: more flexible types

* luasnip: changed options to be more flexible

* luasnip: added example

* luasnip: added package option

plugins/default.nix

@@ -32,6 +32,8 @@
 
     ./pluginmanagers/packer.nix
 
+    ./snippets/luasnip
+
     ./statuslines/airline.nix
     ./statuslines/lightline.nix
     ./statuslines/lualine.nix

plugins/helpers.nix

@@ -23,6 +23,8 @@ rec {
     else if builtins.isString args then
       # This should be enough!
       escapeShellArg args
+    else if builtins.isPath args then
+      escapeShellArg args
     else if builtins.isBool args then
       "${ boolToString args }"
     else if builtins.isFloat args then

plugins/snippets/luasnip/default.nix

@@ -0,0 +1,98 @@
+{ pkgs, config, lib, ... }:
+with lib;
+let
+  cfg = config.plugins.luasnip;
+  helpers = import ../../helpers.nix { lib = lib; };
+in
+{
+  options.plugins.luasnip = {
+    enable = mkEnableOption "Enable luasnip";
+
+    package = mkOption {
+      default = pkgs.vimPlugins.luasnip;
+      type = types.package;
+    };
+
+    fromVscode = mkOption {
+      default = [ ];
+      example = ''
+        [
+          {}
+          {
+            paths = ./path/to/snippets;
+          }
+        ]
+        # generates:
+        # 
+        # require("luasnip.loaders.from_vscode").lazy_load({})
+        # require("luasnip.loaders.from_vscode").lazy_load({['paths'] = {'/nix/store/.../path/to/snippets'}})
+        #
+      '';
+      type = types.listOf (types.submodule {
+        options = {
+          lazyLoad = mkOption {
+            type = types.bool;
+            default = true;
+            description = ''
+              Whether or not to lazy load the snippets
+            '';
+          };
+
+          # TODO: add option to also include the default runtimepath
+          paths = mkOption {
+            default = null;
+            type = with types; nullOr (oneOf
+              [
+                str
+                path
+                helpers.rawType
+                (listOf (oneOf
+                  [
+                    str
+                    path
+                    helpers.rawType
+                  ]))
+              ]);
+          };
+
+          exclude = mkOption {
+            type = types.nullOr (types.listOf types.str);
+            default = null;
+            description = ''
+              List of languages to exclude, by default is empty.
+            '';
+          };
+
+          include = mkOption {
+            type = types.nullOr (types.listOf types.str);
+            default = null;
+            description = ''
+              List of languages to include, by default is not set.
+            '';
+          };
+        };
+      });
+    };
+
+    # TODO: add support for snipmate
+    # TODO: add support for lua
+  };
+
+  config =
+    let
+
+      fromVscodeLoaders = lists.map
+        (loader:
+          let
+            options = attrsets.getAttrs [ "paths" "exclude" "include" ] loader;
+          in
+          ''
+            require("luasnip.loaders.from_vscode").${optionalString loader.lazyLoad "lazy_"}load(${helpers.toLuaObject options})
+          '')
+        cfg.fromVscode;
+    in
+    mkIf cfg.enable {
+      extraPlugins = [ cfg.package ];
+      extraConfigLua = concatStringsSep "\n" fromVscodeLoaders;
+    };
+}