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
92
93
94
95
96
97
98
99
100
101
102
103
104
|
/*
* An example of initializers and scoping rules
*
* Copyright © 2001 Keith Packard
* All Rights Reserved. See the file COPYING in this directory
* for licensing information.
*/
continuation c;
/*
* Static initializer example
*/
function stat ()
{
int x = 1;
function bar ()
{
static int qq = 37;
/*
* Create an array containing two objects.
*
* During the evaluation of the first initializer,
* a continuation is captured. Thus the initializer
* can be reentered at this point.
*
* The second continuation demonstrates creating an
* anonymous lambda and using a variety of values
* which are in scope
*/
static int[*] y = (int[2]) {
(int l = setjmp (&c, 1)),
l + (func (a) { return a + ++l + x; }) (++x) + ++qq
};
return ++y[0] + ++y[1];
}
return bar () + bar();
}
/*
* Some sample values from this function. These are rather
* hard to figure out from the code above.
*/
stat () /* 98 */
longjmp (c, 0) /* 98 */
longjmp (c, 1) /* 110 */
/*
* Global initializer example
*/
int glob_x = 2;
function glob ()
{
int x = 2;
function bar ()
{
int z = 3;
global q = 7;
function bletch ()
{
/*
* This initializer is run in glob's static initializer context
* Again, an anonymous lambda is used to create a local name
* context to hold a variety of name types
*/
global y = (func (a) {
static l_s = 7;
global l_g = 8;
auto l_a = 9;
return a + q + l_s + l_g + l_a;
}) (glob_x);
/*
* This initializer is run in bletch's static initializer context
* Hence it can reference dynamic variables anywhere above
* bletch, static variables within bletch and global variables
* anywhere
*/
static u = z + glob_x;
static t = u + q;
return ++y + u + t;
}
return bletch () + x;
}
return bar ();
}
/*
* Sample output from this function
*/
glob() /* 53 */
glob() /* 54 */
glob() /* 55 */
/*
* Modify current glob_x value, has no effect on y value,
* but does change u value
*/
glob_x = 47;
glob () /* 146 */
|
