From: ara.t.howard@...
Date: 2006-09-28T02:59:50+09:00
Subject: Re: problem with ".scan"

On Thu, 28 Sep 2006, Peter Bailey wrote:

> unknown wrote:
>> On Thu, 28 Sep 2006, Peter Bailey wrote:
>>
>>>> -a
>>>
>>> Sorry. It's a bit much. That's why I was holding back. Here's the whole
>>> script.
>>
>> <snip>
>>
>>> Dir.glob("*.ps").each do |psfile|
>>>  file_contents = File.read(psfile)
>>>  file_contents.scan(/\%\%Pages: (\d{1,5})[ ]+\n/) do
>>>    totalpages = $1
>>>    if (totalpages.to_i % 2) !=0 then
>>>      newtotalpages = totalpages.to_i + 1
>>>      file_contents << "\%\%Blank page for Asura.\n\%\%Page:
>>                       ^^
>>                       ^^
>>                       ^^
>>                       ^^
>>                       the modification is question
>>>       #{newtotalpages.to_i}\nshowpage\n"
>>>      File.open(psfile, "w") { |f| f.print file_contents }
>>>      FileUtils.touch(psfile)
>>>    end
>>
>> so, ruby is correct, you are modifying a string while in an in-progress
>> scan
>> block.  easy-cheasy.
>>
>> kind regards.
>>
>> -a
>
>
> Thanks. I ended the scan block before doing any file writing. That
> seemed to do the trick. It still confuses me, though, because, this code
> was borrowed from an existing script that I've been using for 6 months,
> and, that part of it is just as you see it above.

probably because totalpages is always 1 - it's never even - in your new script
the number of pages is always 2 (or 0) i'm guessing, and so the bug is
triggered.  if i we're you i'd update the other script - it's a bug in
waiting.

regards.

-a
-- 
in order to be effective truth must penetrate like an arrow - and that is
likely to hurt. -- wei wu wei