Hi again
Boy, all those problems...
Try running the attached script. It gives the following error:
** Script Error: middle has no value.
** Where: copy skip list middle
OK... well, the line with "copy skip list middle" is just _below_ this line:
list1: sort-list (copy/part list middle) :cfunc
which doesn't produce an error, and since I don't touch 'middle between those
two lines, 'middle _has_ to have a value!
I suspect that 'use is broken. For recursion I need 'use, otherwise the
recursive calls will mess with the variables. But it seems like 'use causes
recursive calls to unset the used variables.
Any ideas what else could be wrong, before I send this to [EMAIL PROTECTED]?
I know that it might just be me having made a stupid bug in the attached
code.
BTW, the attached function is a merge-sort, which I had to write since
bubble-sort is too slow, and since I still haven't got sort/compare working
(will be sending this bug report to [EMAIL PROTECTED] soon too, unless
somebody can see if there's an error in my code). I know that merge-sort can
be implemented in a less memory-hungry way, but I'd like to get this thing
working first.
Kind regards,
--
Ole Friis <[EMAIL PROTECTED]>
Amiga is a trademark of Amiga Inc.
REBOL []
sort-list: func [list cfunc] [
use [list1 list2 middle] [
if (length? list) > 1 [
; Recursively sort the two halves of list
middle: to-integer ((length? list) / 2)
list1: sort-list (copy/part list middle) :cfunc
list2: sort-list (copy skip list middle) :cfunc
; Merge list1 and list2 into list
clear list
while [(not tail? list1) and (not tail? list2)] [
either (cfunc (first list1) (first list2)) [
append list first list1
list1: next list1
] [
append list first list2
list2: next list2
]
list: next list
]
append list list1
append list list2
]
]
list
]
test-list: [6 5 3 8 9]
sort-list test-list :greater?
