[REBOL] Re: Loop with negative count
From: pwawood::gmail::com at: 28-Dec-2006 10:50
Tim
Why don't you protect your code against changes in undocumented
behaviour by either using:
Loop max 0 possible-negative-count
or
if positive? count [loop count [code]]
I thought that there would be a time penalty in doing so but my tests
show it is hardly noticeable. (Providing my tests are correct).
Regards
Peter
Test Source:
REBOl []
count: to integer! ask "Enter an integer - positive of negative: "
times: 100000
start: now/time/precise
loop times
[
test: copy []
loop count [append test "hello"]
]
end: now/time/precise
print "test 1"
print [times "loops with count of " count " took: " subtract end start]
start: now/time/precise
loop times
[
test: copy []
loop max 0 count [append test "hello"]
]
end: now/time/precise
print "test 2"
print [times "loops with count of " count " took: " subtract end start]
start: now/time/precise
loop times
[
test: copy []
if positive? count [loop count [append test "hello"]]
]
end: now/time/precise
print "test 3"
print [times "loops with count of " count " took: " subtract end start]
>> do %tt.r
Script: "Untitled" (none)
Enter an integer - positive of negative: 2
test 1
100000 loops with count of 2 took: 0:00:02.404771
test 2
100000 loops with count of 2 took: 0:00:02.365083
test 3
100000 loops with count of 2 took: 0:00:02.41553
>> do %tt.r
Script: "Untitled" (none)
Enter an integer - positive of negative: 8
test 1
100000 loops with count of 8 took: 0:00:08.297555
test 2
100000 loops with count of 8 took: 0:00:07.476637
test 3
100000 loops with count of 8 took: 0:00:07.236025
>> do %tt.r
Script: "Untitled" (none)
Enter an integer - positive of negative: -4
test 1
100000 loops with count of -4 took: 0:00:00.843843
test 2
100000 loops with count of -4 took: 0:00:00.683992
test 3
100000 loops with count of -4 took: 0:00:00.466519
>> do %tt.r
Script: "Untitled" (none)
Enter an integer - positive of negative: -55
test 1
100000 loops with count of -55 took: 0:00:00.902979
test 2
100000 loops with count of -55 took: 0:00:00.600534
test 3
100000 loops with count of -55 took: 0:00:00.513414
>> do %tt.r
Script: "Untitled" (none)
Enter an integer - positive of negative: 30
test 1
100000 loops with count of 30 took: 0:00:37.077424
test 2
100000 loops with count of 30 took: 0:00:33.583799
test 3
100000 loops with count of 30 took: 0:00:38.293701
