add plugin that removes everything except JSDoc comments from source files (#304)

plugins/commentsOnly.js

@@ -0,0 +1,16 @@
+/**
+ * @overview Remove everything in a file except JSDoc-style comments. By enabling this plugin, you
+ * can document source files that are not valid JavaScript (including source files for other
+ * languages).
+ * @module plugins/commentsOnly
+ * @author Jeff Williams <jeffrey.l.williams@gmail.com>
+ */
+
+exports.handlers = {
+    beforeParse: function(e) {
+        // a JSDoc comment looks like: /**[one or more chars]*/
+        var comments = e.source.match(/\/\*\*[\s\S]+?\*\//g);
+        e.source = comments.join('\n\n');
+        console.log('source: ' + e.source);
+    }
+};