fix WOQL.select and WOQL.distinct with variables (#271)

Co-authored-by: Francesca-Bit <francesca@terminusdb.com>

Author: Francesca-Bit

lib/query/woqlQuery.js

@@ -312,8 +312,6 @@ WOQLQuery.prototype.comment = function (comment, subquery) {
  */
 
 WOQLQuery.prototype.select = function (...varNames) {
-  // if (list && list[0] === 'args')
-  // return ['variable_list', 'query']
   if (this.cursor['@type']) this.wrapCursorWithAnd();
   this.cursor['@type'] = 'Select';
   if (!varNames || varNames.length <= 0) {
@@ -324,7 +322,7 @@ WOQLQuery.prototype.select = function (...varNames) {
   *@type {any}
   */
   let embedquery = false;
-  if (typeof last === 'object' && last.json) {
+  if (typeof last === 'object' && !(last instanceof Var) && last.json) {
     embedquery = varNames.pop();
   } // else var embedquery = false
   this.cursor.variables = this.rawVarList(varNames);
@@ -350,7 +348,7 @@ WOQLQuery.prototype.distinct = function (...varNames) {
      * @type {any}
      */
   let embedquery = false;
-  if (typeof last === 'object' && last.json) {
+  if (typeof last === 'object' && !(last instanceof Var) && last.json) {
     embedquery = varNames.pop();
   } // else var embedquery = false
   this.cursor.variables = this.rawVarList(varNames);