Support modulo operator '%'

The spec is underspecified in what should happen if the left hand side
is a float. This commit decides that the result is undefined (unknown).

The spec is also underspecified in what should happen if either the left
hand side or the right hand side is negative. This commit decides to use
the behaviour of Erlang `rem`.

Author: ansd

deps/rabbit/src/rabbit_amqp_filter_sql.erl

@@ -140,7 +140,8 @@ eval0({Op, Expr1, Expr2}, Msg)
   when Op =:= '+' orelse
        Op =:= '-' orelse
        Op =:= '*' orelse
-       Op =:= '/' ->
+       Op =:= '/' orelse
+       Op =:= '%' ->
     arithmetic(Op, eval0(Expr1, Msg), eval0(Expr2, Msg));
 
 %% Unary operators
@@ -209,6 +210,8 @@ arithmetic('*', Left, Right) when is_number(Left) andalso is_number(Right) ->
     Left * Right;
 arithmetic('/', Left, Right) when is_number(Left) andalso is_number(Right) andalso Right /= 0 ->
     Left / Right;
+arithmetic('%', Left, Right) when is_integer(Left) andalso is_integer(Right) andalso Right =/= 0 ->
+    Left rem Right;
 arithmetic(_, _, _) ->
     undefined.