listed theme names and updated future work

guides/theming.md

@@ -26,6 +26,9 @@ single css file for Angular Material in your app.
 You can include a theme file directly into your application from
 `@angular/material/core/theming/prebuilt`
 
+Available pre-built themes:
+<!-- directory(/src/lib/core/theming/prebuilt/) -->
+
 If you're using Angular CLI, this is as simple as including one line
 in your `styles.css`  file:
 ```css
@@ -133,3 +136,4 @@ For more details about theming your own components, see [theming-your-components
 ### Future work
 * Once CSS variables (custom properties) are available in all the browsers we support,
   we will explore how to take advantage of them to make theming even simpler.
+* More prebuilt themes will be added as development continues.

tools/gulp/tasks/docs.ts

@@ -24,6 +24,11 @@ const EXAMPLE_PATTERN = /<!--\W*example\(([^)]+)\)\W*-->/g;
 // documentation page. Using a RegExp to rewrite links in HTML files to work in the docs.
 const LINK_PATTERN = /(<a[^>]*) href="([^"]*)"/g;
 
+// Some docs require maintaining a list of files.
+// Supplying a directory as a argument will list the files at that directory.
+// Supplying no arguments will list the files at the root of that folder.
+const DIRECTORY_PATTERN = /<!--\W*directory\(([^)]+)\)\W*-->/g;
+
 // HTML tags in the markdown generated files that should receive a .docs-markdown-${tagName} class
 // for styling purposes.
 const MARKDOWN_TAGS_TO_CLASS_ALIAS = [
@@ -107,10 +112,30 @@ function transformMarkdownFiles(buffer: Buffer, file: any): string {
     // If the head is not prepended to the replaced value, then the first match will be lost.
     `${head} href="${fixMarkdownDocLinks(link, file.path)}"`
   );
-
+
+  /* Replace <!-- directory(..) --> comments with HTML elements. */
+  content = content.replace(DIRECTORY_PATTERN, (match: string, directory: string) =>
+    `<div>${listFiles(directory,file.path)}</div>`
+  );
+
   return content;
 }
 
+/** Returns a list of files from a given directory */
+function listFiles(directory: string, filePath: string): string {
+  // If no directory is supplied, take the directory from the filePath.
+  if(directory === '') {
+    directory = .dirname(filePath.base);
+  }
+
+  // Get all the files in the directory, just store their names in a list.
+  let files = gulp.src(directory).map((path) => {
+    return '<li>' + path.basename() + '</li>';
+  }).join();
+
+  return '<ul>' + files + '</ul>';
+}
+
 /** Fixes paths in the markdown files to work in the material-docs-io. */
 function fixMarkdownDocLinks(link: string, filePath: string): string {
   // As for now, only markdown links that are relative and inside of the guides/ directory