The elasticsearch datasource will now better handle language specifics when…

The elasticsearch datasource will now better handle language specifics when making the search partial (ie for search as you type).  This means the search field will now support significantly more complex searches such as:

    title:foo AND title:bar OR baz
    title:mysql AND [3306 TO 3308]
    web~
    title:foo AND -bar

src/app/services/elasticsearch/es-datasource.js

@@ -209,7 +209,21 @@ function (angular, _, config, kbn, moment) {
     };
 
     ElasticDatasource.prototype.searchDashboards = function(queryString) {
-      queryString = queryString.toLowerCase().replace(' and ', ' AND ');
+      var endsInOpen = function(string, opener, closer) {
+        var character;
+        var count = 0;
+        for (var i=0; i<string.length; i++) {
+          character = string[i];
+
+          if (character == opener) {
+            count++;
+          } else if (character == closer) {
+            count--;
+          }
+        }
+
+        return count > 0;
+      }
 
       var tagsOnly = queryString.indexOf('tags!:') === 0;
       if (tagsOnly) {
@@ -221,7 +235,21 @@ function (angular, _, config, kbn, moment) {
           queryString = 'title:';
         }
 
-        if (queryString[queryString.length - 1] !== '*') {
+        // make this a partial search if we're not in some reserved portion of the language,  comments on conditionals, in order:
+        // 1. ends in reserved character, boosting, boolean operator ( -foo)
+        // 2. typing a reserved word like AND, OR, NOT
+        // 3. open parens (groupiing)
+        // 4. open " (term phrase)
+        // 5. open [ (range)
+        // 6. open { (range)
+        // see http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html#query-string-syntax
+        if (!queryString.match(/(\*|\]|}|~|\)|"|^\d+|\s[\-+]\w+)$/) &&
+            !queryString.match(/[A-Z]$/) &&
+            !endsInOpen(queryString, '(', ')') &&
+            !endsInOpen(queryString, '"', '"') &&
+            !endsInOpen(queryString, '[', ']') && !endsInOpen(queryString, '[', '}') &&
+            !endsInOpen(queryString, '{', ']') && !endsInOpen(queryString, '{', '}')
+        ){
           queryString += '*';
         }
       }