original.name="While_Valid_67"
======
>>> main.whiley
type nat is (int x) where x >= 0
property sorted(int[] arr, int n) -> (bool r):
return n >= 1 && n <= |arr| &&
all { i in 1..n | arr[i-1] < arr[i] }
function create(int start, int end) -> (int[] result)
requires start < end
ensures sorted(result,|result|) && |result| == (end - start):
//
nat i = 1
nat length = (end - start)
int[] items = [start;length]
//
while i < length
where i > 0 && |items| == length
where sorted(items,i) && items[i-1] < (start+i):
items[i] = start + i
i = i + 1
// Done
return items
public export method test():
//
assume create(0,1) == [0]
//
assume create(0,2) == [0,1]
//
assume create(0,3) == [0,1,2]
//
assume create(1,4) == [1,2,3]
//
assume create(2,4) == [2,3]
//
assume create(3,4) == [3]
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