SYNOPSIS
        void walk_mapping(mapping m, string func, mixed extra,...)
        void walk_mapping(mapping m, string func, string|object ob
                                                , mixed extra,...)
        void walk_mapping(mapping m, closure cl, mixed extra,...)

DESCRIPTION
        Calls ob->func(key, value1, ..., valueN, extra,...) resp. applies
        the closure to every entry in the mapping. The keys are passed
        by value, the values are passed by reference and can be
        changed in the function.

        Any number of extra arguments is accepted and passed. These arguments
        must not be protected references like &(i[]).

        If <ob> is omitted, or neither a string nor an object, it
        defaults to this_object().

HISTORY
        Introduced in 3.2@61

SEE ALSO
        map(E), filter(E)