define
[ ]
----

iter
first
last
seek-lt a
seek-lt z
seek-ge a
seek-ge z
----
.
.
.
.
.
.

define
[ a.SET.1-b.SET.2 ]
----

iter
last
----
000001:[a#1,1-b#2,1]

iter
first
next
prev
prev
----
000001:[a#1,1-b#2,1]
.
000001:[a#1,1-b#2,1]
.

iter
seek-ge a
seek-ge b
seek-ge c
----
000001:[a#1,1-b#2,1]
000001:[a#1,1-b#2,1]
.

iter
seek-lt a
seek-lt b
seek-lt z
----
.
000001:[a#1,1-b#2,1]
000001:[a#1,1-b#2,1]

define
[ b.SET.1-c.SET.2 ]
----

iter
seek-ge a
seek-ge d
seek-lt a
seek-lt z
----
000001:[b#1,1-c#2,1]
.
.
000001:[b#1,1-c#2,1]


define
a.SET.1-b.SET.2 [ c.SET.3-d.SET.4 e.SET.5-f.SET.6 ] g.SET.7-h.SET.8
----

iter
first
prev
last
next
----
000002:[c#3,1-d#4,1]
.
000003:[e#5,1-f#6,1]
.

iter
seek-ge a
seek-ge b
seek-ge c
seek-ge h
prev
----
000002:[c#3,1-d#4,1]
000002:[c#3,1-d#4,1]
000002:[c#3,1-d#4,1]
.
000003:[e#5,1-f#6,1]

iter
seek-lt b
next
seek-lt a
next
seek-lt z
----
.
000002:[c#3,1-d#4,1]
.
000002:[c#3,1-d#4,1]
000003:[e#5,1-f#6,1]

define
a.SET.1-b.SET.2 c.SET.3-d.SET.4 e.SET.5-f.SET.6 g.SET.7-h.SET.8 [ ]
----

iter
seek-ge cat
seek-lt cat
first
last
----
.
.
.
.