code: public Context merge(final Vars vars, final Out out) {
          try {
              return prepareAst()
                      .execute(this, out, vars);
          } catch (Exception e) {
              throw completeException(e);
          }
      }
docs: Merge this template.
  
  @param vars
  @param out
  @return Context
  @throws ScriptRuntimeException
  @throws ParseException