/*
* Prepend a new element to the list. A pointer to the modified list
* is returned. Note that this function may or may not destructively
* modify the list; callers should always use this function's return
* value, rather than continuing to use the pointer passed as the
* second argument.
*
* Caution: before Postgres 8.0, the original List was unmodified and
* could be considered to retain its separate identity. This is no longer
* the case.
*/
List *
lcons(void *datum, List *list)
{
Assert(IsPointerList(list));
if (list == NIL)
list = new_list(T_List);
else
new_head_cell(list);
lfirst(list->head) = datum;
return list;
}
/*
* Prepend an OID to the list. See lcons()
*/
List *
lcons_oid(Oid datum, List *list)
{
Assert(IsOidList(list));
if (list == NIL)
list = new_list(T_OidList);
else
new_head_cell(list);
lfirst_oid(list->head) = datum;
check_list_invariants(list);
return list;
}
/*
* Prepend an integer to the list. See lcons()
*/
List *
lcons_int(int datum, List *list)
{
Assert(IsIntegerList(list));
if (list == NIL)
list = new_list(T_IntList);
else
new_head_cell(list);
lfirst_int(list->head) = datum;
check_list_invariants(list);
return list;
}
