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comparison lib/js/urweb.js @ 969:001edfbe2561

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Iterative versions of some JavaScript list functions
author Adam Chlipala <adamc@hcoop.net>
date Tue, 22 Sep 2009 09:53:05 -0400
parents 1b80b9df0d32
children 8371d12ae63f
comparison
equal deleted inserted replaced
968:b8048f6e25ef 969:001edfbe2561
1 // Lists 1 // Lists
2 2
3 function cons(v, ls) { 3 function cons(v, ls) {
4 return { next : ls, data : v }; 4 return { next : ls, data : v };
5 } 5 }
6 function rev(ls) {
7 var acc = null;
8 for (; ls; ls = ls.next)
9 acc = cons(ls.data, acc);
10 return acc;
11 }
6 function concat(ls1, ls2) { 12 function concat(ls1, ls2) {
7 return (ls1 ? cons(ls1.data, concat(ls1.next, ls2)) : ls2); 13 var acc = ls2;
14 ls1 = rev(ls1);
15 for (; ls1; ls1 = ls1.next)
16 acc = cons(ls1.data, acc);
17 return acc;
8 } 18 }
9 function member(x, ls) { 19 function member(x, ls) {
10 for (; ls; ls = ls.next) 20 for (; ls; ls = ls.next)
11 if (ls.data == x) 21 if (ls.data == x)
12 return true; 22 return true;
13 return false; 23 return false;
14 } 24 }
15 function remove(x, ls) { 25 function remove(x, ls) {
16 return (ls ? (ls.data == x ? ls.next : cons(ls.data, remove(x, ls.next))) : null); 26 var acc = null;
27
28 for (; ls; ls = ls.next)
29 if (ls.data == x)
30 return concat(acc, ls.next);
31 else
32 acc = cons(ls.data, acc);
33
34 return ls;
17 } 35 }
18 function union(ls1, ls2) { 36 function union(ls1, ls2) {
19 return (ls1 ? (member(ls1.data, ls2) ? union(ls1.next, ls2) : cons(ls1.data, union(ls1.next, ls2))) : ls2); 37 var acc = ls2;
38
39 for (; ls1; ls1 = ls1.next)
40 if (!member(ls1.data, ls2))
41 acc = cons(ls1.data, acc);
42
43 return acc;
20 } 44 }
21 function length(ls) { 45 function length(ls) {
22 return (ls ? 1 + length(ls.next) : 0); 46 var acc = 0;
47
48 for (; ls; ls = ls.next)
49 ++acc;
50
51 return acc;
23 } 52 }
24 53
25 54
26 // Error handling 55 // Error handling
27 56
61 } 90 }
62 91
63 function doExn(v) { 92 function doExn(v) {
64 if (v == null || v.uw_error == null) { 93 if (v == null || v.uw_error == null) {
65 var s = (v == null ? "null" : v.toString()); 94 var s = (v == null ? "null" : v.toString());
95 if (v != null && v.fileName && v.lineNumber)
96 s += " (" + v.fileName + ":" + v.lineNumber + ")";
66 runHandlers("Fail", failHandlers, s); 97 runHandlers("Fail", failHandlers, s);
67 } 98 }
68 } 99 }
69 100
70 var disconnectHandlers = null; 101 var disconnectHandlers = null;