/* Tuple object interface */

/*
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Another generally useful object type is an tuple of object pointers.
This is a mutable type: the tuple items can be changed (but not their
number).  Out-of-range indices or non-tuple objects are ignored.

*** WARNING *** settupleitem does not increment the new item's reference
count, but does decrement the reference count of the item it replaces,
if not nil.  It does *decrement* the reference count if it is *not*
inserted in the tuple.  Similarly, gettupleitem does not increment the
returned item's reference count.
*/

typedef struct {
	OB_VARHEAD
	object *ob_item[1];
} tupleobject;

extern typeobject Tupletype;

#define is_tupleobject(op) ((op)->ob_type == &Tupletype)

extern object *newtupleobject PROTO((int size));
extern int gettuplesize PROTO((object *));
extern object *gettupleitem PROTO((object *, int));
extern int settupleitem PROTO((object *, int, object *));

/* Macro, trading safety for speed */
#define GETTUPLEITEM(op, i) ((op)->ob_item[i])