add support for FreeDesktop config file

src/languages/freedesktop.js

@@ -0,0 +1,86 @@
+/*
+Language: FreeDesktop Configs
+Description: FreeDesktop Config Specification file format
+Contributors: Lee Yunjin <[email protected]>
+Category: common, config
+Website: https://www.freedesktop.org/
+*/
+export default function(hljs) {
+  const FIELD_CODES = {
+    className: 'variable',
+    match: /%[a-zA-Z]/,
+    relevance: 1
+  };
+
+  const STRING = {
+    className: 'string',
+    begin: /"/,
+    end: /"/,
+    contains: [ hljs.BACKSLASH_ESCAPE ],
+    relevance: 0
+  };
+
+  const COMMENT = {
+    className: 'comment',
+    begin: /[#]/,
+    end: /$/,
+    relevance: 0
+  };
+
+  const SECTION = {
+    className: 'section',
+    begin: /^\[(Desktop Entry|Unit|Service|Install|Socket|Mount|Automount|Swap|Path|Timer|Slice|Scope|Manager|connection|ipv4|wifi|wifi-security|ipv6|802-3-ethernet|802-11-wireless|802-11-wireless-security|vpn|Journal|Bridge|Desktop Action\s+[A-Za-z0-9_-]+)\]$/,
+    relevance: 10
+  };
+
+  const KEY_NAME = {
+    className: 'attr',
+    begin: /^[A-Za-z0-9_-]+(\[[A-Za-z0-9_@.]+\])?/,
+    end: /\s*=/,
+    excludeEnd: true,
+    relevance: 10
+  };
+
+  const OPERATOR = {
+    className: 'operator',
+    match: /=/,
+    relevance: 0
+  };
+
+  const VALUE = {
+    begin: /=\s*/,
+    end: /$/,
+    excludeBegin: true,
+    contains: [
+      STRING,
+      {
+        className: 'literal',
+        match: /\b(Application|Link|Directory|forking|oneshot|OneShot|true|false|True|False)\b/,
+        relevance: 10
+      }
+    ]
+  };
+
+  const KEY_VALUE = {
+    begin: /^([A-Za-z0-9_-]+(\[[A-Za-z0-9_@.]+\])?)\s*=/,
+    returnBegin: true,
+    contains: [
+      FIELD_CODES,
+      KEY_NAME,
+      OPERATOR,
+      VALUE
+    ]
+  };
+
+  return {
+    name: 'FreeDesktop configuration format',
+    aliases: ['desktop', 'service', 'mount', 'socket', 'timer', 'nmconnection', 'systemd', 'freedesktop'],
+    case_insensitive: false,
+    contains: [
+      COMMENT,
+      SECTION,
+      KEY_VALUE
+    ]
+  };
+}
+