Deleting lines within a 'repeat for each' loop

[Björnke von Gierke]

On Dienstag, Aug 19, 2003, at 10:21 Europe/Zurich, Jan Schenkel wrote:

>> ...
>> on mouseUp
>>
>>    put ".ds_store" & return & "Help File 1.xml" &
>> return & "Help File
>> 3.xml" into fileList
>>
>>    put 1 into i
>>
>>    breakpoint
>>    repeat for each line currLine in fileList
>>      delete line i of fileList
>>      add 1 to i
>>    end repeat
>>
>> end mouseUp
>> ...
> ...
> The reason why you are getting such 'strange' results
> is that in a repeat for each loop, the engine
> remembers where the current line ended, and that's
> where it starts looking for the next lineDelimiter.
> So in this case, it finds the first line delimiter at
> position 9. Then you delete the first line, but the
> next repeat loop starts looking at position 10 in the
> changed variable. The next lineDelimiter is at new
> position 16, so it thinks that line 2 stretches from
> position 10 to 16 -- which explains why it gives you "
> 1.xml" the next time around.
> Etcetera, etcetera.
>
> As you shouldn't tinker with the variable you're
> interating over, here are a few alternative approaches
> to your goal :
> ...

Eh? I always thought that the repeat for each loop copies the content 
it loops over and then uses that too loop. This is so that looping in 
fields is not slower then looping in a variable. In fact looping a 
variable IS NOT faster then looping a field (I tested that). 
Unfortunately the fact is that deleting lines in a fashion as the above 
WILL result in rubbish. I am kinda lost, shouldn't the one fact 
contradict the other????