blob: 7e087f959326bbf42ca56a7b69895771957a3327 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
|
interface DList[T] {
var list: seq[T]
invariant
|list| > 0
constructor Init(t: T)
list := [t]
constructor Double(p: T, q: T)
list := [p q]
method List() returns (ret: seq[T])
ret := list
method Size() returns (ret: int)
ret := |list|
method Get(idx: int) returns (ret: T)
requires 0 <= idx && idx < |list|
ret := list[idx]
method Find(n: T) returns (ret: bool)
ret := n in list
}
datamodel DList[T] {
var data: T
var next: DList[T]
var prev: DList[T]
frame
next
invariant
next = null ==> list = [data]
next != null ==> (list = [data] + next.list
&& next.prev = this)
prev != null ==> prev.next = this
}
|
