constraint <-   ws? app_name ws? between_op  ws? version ws? "," ws? version ws? !.
              / ws? app_name ws? constraint_op ws? version ws? !.
              / ws? app_name ws? !.

           `
           case Node of
                [_,AppName,_, _] ->
                    {ok, AppName};
                [_,AppName,_,Op,_,Vsn,_, _] ->
                    {ok,
                        {AppName,
                         rlx_goal_utils:to_vsn(Vsn),
                         rlx_goal_utils:to_op(Op)}};
                [_,AppName,_,Op,_,Vsn1,_,_,_,Vsn2,_,_] ->
                    {ok,
                        {AppName,
                         rlx_goal_utils:to_vsn(Vsn1),
                         rlx_goal_utils:to_vsn(Vsn2),
                         rlx_goal_utils:to_op(Op)}};
                _ ->
                 io:format("~p~n", [Node])
           end
           ` ;

ws <- [ \t\n\s\r] ;

app_name <- [a-zA-Z0-9_]+
         ` erlang:list_to_atom(erlang:binary_to_list(erlang:iolist_to_binary(Node))) ` ;

between_op <-
             ":" ws? ( "btwn" / "between" ) ws? ":"
                   ` case Node of
                       [C,_,Op,_,C] -> erlang:iolist_to_binary([C,Op,C]);
                       _ -> Node
                      end
                   ` ;

constraint_op <- "=" / "-" / "<=" / "<" / "~>" / ">=" / ">" / word_constraint_op / ":" ;

word_constraint_op <-
                   ":" ws? ( "gte" / "lte" / "gt" / "lt"  / "pes" ) ws? ":"
                   ` case Node of
                           [C,_,Op,_,C] -> erlang:iolist_to_binary([C,Op,C]);
                       _ -> Node
                      end
                   ` ;


version <- [0-9a-zA-Z-+.]+ ;

%% This only exists to get around a bug in erlang where if
%% warnings_as_errors is specified `nowarn` directives are ignored

 `-compile(export_all).`