docs: enable syntax highlighting for cue

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

tools/daggosaurus/docusaurus.config.js

@@ -19,7 +19,7 @@ module.exports = {
   themeConfig: {
     sidebarCollapsible: false,
     prism: {
-      defaultLanguage: "go",
+      theme: require("prism-react-renderer/themes/vsDark"),
     },
     navbar: {
       logo: {

tools/daggosaurus/src/theme/prism-include-languages.js

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+import ExecutionEnvironment from "@docusaurus/ExecutionEnvironment";
+import siteConfig from "@generated/docusaurus.config";
+
+const prismIncludeLanguages = (PrismObject) => {
+  if (ExecutionEnvironment.canUseDOM) {
+    const {
+      themeConfig: { prism: { additionalLanguages = [] } = {} },
+    } = siteConfig;
+    window.Prism = PrismObject;
+    additionalLanguages.forEach((lang) => {
+      require(`prismjs/components/prism-${lang}`); // eslint-disable-line
+    });
+    require("./prism.cue.js");
+    delete window.Prism;
+  }
+};
+
+export default prismIncludeLanguages;

tools/daggosaurus/src/theme/prism.cue.js

@@ -0,0 +1,32 @@
+Prism.languages.cue = Prism.languages.extend("clike", {
+  // https://github.com/PrismJS/prism/blob/master/components/prism-swift.js
+  string: {
+    pattern: /(["'`])(?:\\[\s\S]|(?!\1)[^\\])*\1/,
+    greedy: true,
+    inside: {
+      interpolation: {
+        pattern: /\\\#*\((?:[^()]|\([^)]+\))+\)/,
+        inside: {
+          delimiter: {
+            pattern: /^\\\#*\(|\)$/,
+            alias: "variable",
+          },
+        },
+      },
+    },
+  },
+
+  // https://cuelang.org/docs/references/spec/#values
+  keyword: /\b(?:package|import|if|else|for|in|let)\b/,
+  boolean: /\b(?:true|false)\b/,
+  constant: /\b(?:_\|_|_)\b/,
+
+  // https://github.com/PrismJS/prism/blob/master/components/prism-go.js
+  number: /(?:\b0x[a-f\d]+|(?:\b\d+(?:\.\d*)?|\B\.\d+)(?:e[-+]?\d+)?)i?/i,
+  operator:
+    /[*\/%^!=]=?|\+[=+]?|-[=-]?|\|[=|]?|&(?:=|&|\^=?)?|>(?:>=?|=)?|<(?:<=?|=|-)?|:=|\.\.\./,
+
+  // https://cuelang.org/docs/references/spec/#predeclared-identifiers
+  builtin:
+    /\b(?:len|null|bool|int|float|string|bytes|number|u?int(?:8|16|32|64|128)?|rune|float(?:32|64))\b/,
+});