diff --git a/src/structs.h b/src/structs.h
index ce98bce..1a3abcb 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -73,6 +73,7 @@
 typedef struct dictvar_S	dict_T;
 typedef struct partial_S	partial_T;
 typedef struct blobvar_S	blob_T;
+typedef struct tuplevar_S	tuple_T;
 
 typedef struct window_S		win_T;
 typedef struct wininfo_S	wininfo_T;
@@ -1511,7 +1512,8 @@
     VAR_INSTR,		// "v_instr" is used
     VAR_CLASS,		// "v_class" is used (also used for interface)
     VAR_OBJECT,		// "v_object" is used
-    VAR_TYPEALIAS	// "v_typealias" is used
+    VAR_TYPEALIAS,	// "v_typealias" is used
+    VAR_TUPLE		// "v_tuple" is used
 } vartype_T;
 
 // A type specification.
@@ -1679,6 +1681,7 @@
 	class_T		*v_class;	// class value (can be NULL)
 	object_T	*v_object;	// object value (can be NULL)
 	typealias_T	*v_typealias;	// user-defined type name
+	tuple_T		*v_tuple;	// tuple
     }		vval;
 };
 
@@ -1818,6 +1821,21 @@
     char	bv_lock;	// zero, VAR_LOCKED, VAR_FIXED
 };
 
+/*
+ * Structure to hold info about a tuple.
+ */
+struct tuplevar_S
+{
+    garray_T	tv_items;	// tuple items
+    type_T	*tv_type;	// current type, allocated by alloc_type()
+    tuple_T	*tv_copytuple;	// copied tuple used by deepcopy()
+    tuple_T	*tv_used_next;	// next tuple in used tuples list
+    tuple_T	*tv_used_prev;	// previous tuple in used tuples list
+    int		tv_refcount;	// reference count
+    int		tv_copyID;	// ID used by deepcopy()
+    char	tv_lock;	// zero, VAR_LOCKED, VAR_FIXED
+};
+
 typedef int (*cfunc_T)(int argcount, typval_T *argvars, typval_T *rettv, void *state);
 typedef void (*cfunc_free_T)(void *state);
 
@@ -1846,6 +1864,8 @@
     blob_T	*fi_blob;	// blob being used
     char_u	*fi_string;	// copy of string being used
     int		fi_byte_idx;	// byte index in fi_string
+    tuple_T	*fi_tuple;	// tuple being used
+    int		fi_tuple_idx;	// tuple index in fi_tuple
     int		fi_cs_flags;	// cs_flags or'ed together
 } forinfo_T;
 
@@ -2821,6 +2841,15 @@
 } list_stack_T;
 
 /*
+ * structure used for explicit stack while garbage collecting tuples
+ */
+typedef struct tuple_stack_S
+{
+    tuple_T			*tuple;
+    struct tuple_stack_S	*prev;
+} tuple_stack_T;
+
+/*
  * Structure used for iterating over dictionary items.
  * Initialize with dict_iterate_start().
  */
@@ -4692,6 +4721,7 @@
     char_u	*ll_newkey;	// New key for Dict in alloc. mem or NULL.
     type_T	*ll_valtype;	// type expected for the value or NULL
     blob_T	*ll_blob;	// The Blob or NULL
+    tuple_T	*ll_tuple;	// tuple or NULL
     ufunc_T	*ll_ufunc;	// The function or NULL
     object_T	*ll_object;	// The object or NULL, class is not NULL
     class_T	*ll_class;	// The class or NULL, object may be NULL