docs: public final QueryParser.approximately_return approximately() throws RecognitionException {
          QueryParser.approximately_return retval = new QueryParser.approximately_return();
          retval.start = input.LT(1);
  
          CommonTree root_0 = null;
  
          Token WS36=null;
          Token APPROXIMATELY37=null;
          Token WS38=null;
          QueryParser.field_return field35 = null;
  
          QueryParser.value_return value39 = null;
  
  
          CommonTree WS36_tree=null;
          CommonTree APPROXIMATELY37_tree=null;
          CommonTree WS38_tree=null;
  
          try {
              // src/riemann/Query.g:54:2: ( field ( WS )* APPROXIMATELY ( WS )* value )
              // src/riemann/Query.g:54:4: field ( WS )* APPROXIMATELY ( WS )* value
              {
              root_0 = (CommonTree)adaptor.nil();
  
              pushFollow(FOLLOW_field_in_approximately357);
              field35=field();
  
              state._fsp--;
  
              adaptor.addChild(root_0, field35.getTree());
              // src/riemann/Query.g:54:10: ( WS )*
              loop13:
              do {
                  int alt13=2;
                  int LA13_0 = input.LA(1);
  
                  if ( (LA13_0==WS) ) {
                      alt13=1;
                  }
  
  
                  switch (alt13) {
              	case 1 :
              	    // src/riemann/Query.g:54:10: WS
              	    {
              	    WS36=(Token)match(input,WS,FOLLOW_WS_in_approximately359); 
              	    WS36_tree = (CommonTree)adaptor.create(WS36);
              	    adaptor.addChild(root_0, WS36_tree);
  
  
              	    }
              	    break;
  
              	default :
              	    break loop13;
                  }
              } while (true);
  
              APPROXIMATELY37=(Token)match(input,APPROXIMATELY,FOLLOW_APPROXIMATELY_in_approximately362); 
              APPROXIMATELY37_tree = (CommonTree)adaptor.create(APPROXIMATELY37);
              root_0 = (CommonTree)adaptor.becomeRoot(APPROXIMATELY37_tree, root_0);
  
              // src/riemann/Query.g:54:29: ( WS )*
              loop14:
              do {
                  int alt14=2;
                  int LA14_0 = input.LA(1);
  
                  if ( (LA14_0==WS) ) {
                      alt14=1;
                  }
  
  
                  switch (alt14) {
              	case 1 :
              	    // src/riemann/Query.g:54:29: WS
              	    {
              	    WS38=(Token)match(input,WS,FOLLOW_WS_in_approximately365); 
              	    WS38_tree = (CommonTree)adaptor.create(WS38);
              	    adaptor.addChild(root_0, WS38_tree);
  
  
              	    }
              	    break;
  
              	default :
              	    break loop14;
                  }
              } while (true);
  
              pushFollow(FOLLOW_value_in_approximately368);
              value39=value();
  
              state._fsp--;
  
              adaptor.addChild(root_0, value39.getTree());
  
              }
  
              retval.stop = input.LT(-1);
  
              retval.tree = (CommonTree)adaptor.rulePostProcessing(root_0);
              adaptor.setTokenBoundaries(retval.tree, retval.start, retval.stop);
  
          }
          catch (RecognitionException re) {
              reportError(re);
              recover(input,re);
      	retval.tree = (CommonTree)adaptor.errorNode(input, retval.start, input.LT(-1), re);
  
          }
          finally {
          }
          return retval;
      }