m_delete - remove a key from a mapping mapping m_delete(mapping m, mixed element); This efun is only available if COMPAT_32 is defined. It behaves exactly like map_delete(), except that it returns its first argument. Note: the 3.2 version actually returns a copy of the mapping, so for strict compatibility the following simul is suggested:
mapping m_delete(mapping m, mixed element) 
{
    mapping ret = copy(m);
    map_delete(ret, element);
    return ret;
}
However, this version is significantly faster as it avoids the copy. See also: map_delete Tim Hollebeek Beek@ZorkMUD, Lima Bean, IdeaExchange, and elsewhere