blob: dac3234a68d67eafecb92e405f747ed59a8f8731 (
plain) (
blame)
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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
// test "foo = expr" clauses in for comprehensions
import scala.collection.immutable.Queue
import scala.{List=>L}
object Test {
// redefine some symbols to make it extra hard
class List
class Tuple2
def List[A](as: A*) = 5
def firstDigit(x: Int): Int =
x match {
case 0 => 0
case _ if (x<0) => firstDigit(-x)
case _ if (x<10) => x
case _ => firstDigit(x / 10)
}
{
// a basic test case
val input = L.range(0,20)
val oddFirstTimesTwo =
for {x <- input
xf = firstDigit(x)
if xf % 2 == 1}
yield x*2
println(oddFirstTimesTwo)
}
{
// a test case with patterns
val input = L.range(0, 20)
val oddFirstTimesTwo =
for {x <- input
xf = firstDigit(x)
yf = x - firstDigit(x) / 10
(a, b) = (xf - yf, xf + yf)
if xf % 2 == 1}
yield a + b
println(oddFirstTimesTwo)
}
{
// make sure it works on non-Ls
// val input: Queue = Queue.Empty[int].incl(L.range(0,20))
val input = L.range(0, 20).iterator
val oddFirstTimesTwo =
for {x <- input
xf = firstDigit(x)
if xf % 2 == 1}
yield x*2
println(oddFirstTimesTwo.toList)
}
{
// yield the computed value
val input = L.range(0,20)
val oddFirstTimesTwo =
for {x <- input
xf = firstDigit(x)
if xf % 2 == 1}
yield xf*2
println(oddFirstTimesTwo)
}
{
// make sure the function is only called once
var count: Int = 0
def fdct(x: Int) = {
count += 1
firstDigit(x)
}
val input = L.range(0,20)
for {x <- input
xf = fdct(x)
if xf % 2 == 1}
yield xf
println("called " + count + " times")
}
def main(args: Array[String]): Unit = {}
}
|
