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
41
42
43
44
45
46
47
48
49
50
51
52
53
|
object Test extends dotty.runtime.LegacyApp {
def pre(n: Int) = (-n to -1).toStream
def cyc(m: Int) = {
lazy val s: Stream[Int] = (0 until m).toStream #::: s
s
}
def precyc(n: Int, m: Int) = pre(n) #::: cyc(m)
def str(s: Stream[Int]) = {
val b = new StringBuilder
s.addString(b, "", "", "")
b.toString
}
def goal(n: Int, m: Int) = (-n until m).mkString + "..."
// Check un-forced cyclic and non-cyclic streams
assert(str(pre(2)) == pre(2).take(1).toList.mkString + "?")
assert(str(cyc(2)) == cyc(2).take(1).toList.mkString + "?")
assert(str(precyc(2,2)) == precyc(2,2).take(1).toList.mkString + "?")
assert(!pre(2).hasDefiniteSize)
assert(!cyc(2).hasDefiniteSize)
assert(!precyc(2,2).hasDefiniteSize)
// Check forced cyclic and non-cyclic streams
assert(str(pre(2).force) == (-2 to -1).mkString)
assert(str(cyc(2).force) == (0 until 2).mkString + "...")
assert(str(precyc(2,2).force) == (-2 until 2).mkString + "...")
assert(pre(2).force.hasDefiniteSize)
assert(!cyc(2).force.hasDefiniteSize)
assert(!precyc(2,2).force.hasDefiniteSize)
// Special cases
assert(str(cyc(1).force) == goal(0,1))
assert(str(precyc(1,6).force) == goal(1,6))
assert(str(precyc(6,1).force) == goal(6,1))
// Make sure there are no odd/even problems
for (n <- 3 to 4; m <- 3 to 4) {
assert(precyc(n,m).mkString == goal(n,m), s"mkString $n $m")
assert(!precyc(n,m).force.hasDefiniteSize, s"hasDef $n$m")
}
// Make sure there are no cycle/prefix modulus problems
for (i <- 6 to 8) {
assert(precyc(i,3).mkString == goal(i,3), s"mkString $i 3")
assert(precyc(3,i).mkString == goal(3,i), s"mkString 3 $i")
assert(!precyc(i,3).force.hasDefiniteSize, s"hasDef $i 3")
assert(!precyc(3,i).force.hasDefiniteSize, s"hasDef 3 $i")
}
}
|
