[Raleigh-talk] [Perl help] - Multiple substitutions in a file

[Mike South]

Also those \d's aren't going to match A-F are they?

Are you familiar with qr// to let you store a regex bit in a variable?  That
might make some of this more readable.

mike

On Tue, Feb 22, 2011 at 10:58 PM, Matt Nash <mattnashbrowns at gmail.com>wrote:

> Of course, you want actual spaces (not '\s') in the replace string, but you
> knew that.
>
>
> On Tue, Feb 22, 2011 at 9:56 PM, Matt Nash <mattnashbrowns at gmail.com>wrote:
>
>> Hi John,
>>
>> You are reading the entire file into an array of lines, then processing
>> that array using a C-style for loop and interpolating the index var into the
>> search string... and that is the LEAST crazy thing. :)  It works, of course,
>> because it turns out that there are infinitely many ways to do it.
>>
>> For your immediate problem of the search-and-replace, I recommend reading
>> the  whole file into a single string, newlines and all, then using the /gc
>> modifiers in the regex.  Maybe put your colorChange stuff into an array that
>> you loop through, checking the regex for the nth match:
>>
>> @changes = ($change1, $change2, $change3);
>>
>> foreach $change (@changes) {
>>     $wholefile =~
>> s|08\s00\s00\s1C\s\d\d\s\d\d\s\d\d\s\d\d|08\s00\s00\s1C\s$change|gc;
>> }
>>
>> see http://perldoc.perl.org/perlre.html and
>> http://perldoc.perl.org/perlretut.htm<http://perldoc.perl.org/perlretut.html#Using-regular-expressions-in-Perl> for
>> lots of details, but the upshot of the modifiers is: g makes it keep looking
>> for matches; c tells it to remember where it last matched, and start from
>> there on the next match.  You don't have to care what n is, because you are
>> matching your search string exactly as many times as you have changes to
>> make.
>>
>> ...but this project sounds ripe for refactoring, if I may be so bold.
>>  Could it be that what you really need is a templating system?
>>
>> Thanks for bringing some much-needed questions to this list!
>>
>> Matt
>>
>> On Tue, Feb 22, 2011 at 8:31 PM, John Ricker <sephtin+pm-talk at gmail.com>wrote:
>>
>>> Received so much help with the last question (which seems to be
>>> functioning great, btw.. thanks all)... thought I'd try again.  ;)
>>>
>>> Have a script that was recently migrated to Perl from shell/bash, and am
>>> wondering if there's an easy way in Perl to do the following-
>>>
>>> File(s) being modified are hex, and look something like:
>>> ---x---
>>> ...
>>> 08 00 00 00 FF FF FF FF FF FF FF FF 1B 00 00 00 02 01 10 00 28 01 00 00
>>> 09 00 00 00 FF FF FF FF FF FF FF FF 1C 00 00 00 14 00 14 00 0D 00 00 00 00
>>> 00 0D 00 18 00 00 00 11 00 00 00 FF FF FF FF 08 00 00 05 02 0E 00 00 18 00
>>> 00 00 0E 00 00 00 FF FF FF FF 08 00 00 1C 00 00 00 FF 18 00 00 00 09 00 00
>>> 00 FF FF FF FF 08 00 00 11 10 00 00 00 18 00 00 00 0F 00 00 00 FF FF FF FF
>>> 08 00 00 01 11 02 02 01 18 00 00 00 03 00 00 00 FF FF FF FF 08 00 00 01 05
>>> 00 08 01 18 00 00 00 10 00 00 00 FF FF FF FF 08 00 00 05 01 0F 00 00 18 00
>>> 00 00 05 00 00 00 FF FF FF FF 08 00 00 05 01 0F 00 00 18 00 00
>>> ...
>>> ---x---
>>> File(s) contain several occurrences of "08 00 00 1c ## ## ## ##" or more
>>> appropriately for this list: "08\s00\s00\s1C\s\d\d\s\d\d\s\d\d\s\d\d"
>>>
>>>  Now on to the good stuff...  I would like to replace the ## ## ## ##
>>> with my chosen colors, that are being provided by vars... Example:
>>> colorChange1="FF 00 00 FF"
>>> colorChange2="FF FF 00 FF"
>>> colorChange3="FF 00 FF FF"
>>> ...
>>>
>>> I'm wondering how it might be possible, to replace the FIRST occurrence
>>> (in the file, NOT in a line) of "08 00 00 1C ## ## ## ##" with "08 00 00 1C
>>> $colorChange1", the second with "08 00 00 1C $colorChange2", etc.
>>>
>>> More info:
>>> --Script modifies files to theme them, in this case, I'm taking a BINARY
>>> (compiled XML) file, converting it to HEX via xxd, and then changing the
>>> text color for a theme via substitution.
>>> --I originally thought it could be done similar to what sed does... with
>>> s|(08\s00\s00\s1C)\s\d\d\s\d\d\s\d\d\s\d\d|$1$colorChange1|1  (note last
>>> digit...), but testing has shown that this doesn't work as expected.
>>> --Not really related, but in the binary, the colors are actually
>>> backwards, so color - FF AB CD EF becomes binary - EF CD AB FF, but that's
>>> an easy change.
>>> --CURRENTLY in my script, I'm doing this via a sub, passing an array of
>>> the colors, the file, and the file location (directory), and pulling the
>>> file, making the changes, and saving it back out via loop... BUT, because I
>>> couldn't figure out how to just do the multiple replaces... I cheated and
>>> made template files that contain "08 00 00 1C 11 11 11 11" and "08 00 00 1C
>>> 22 22 22 22", so when I iterate through the loop, I just change like so:
>>> for ( $i = 1 ; $i <= $COUNT ; $i++ ) {
>>> ...
>>>     $line =~ s|08\s00\s00\s1c\s$i$i\s$i$i\s$i$i\s$i$i\s|08 00 00 1c
>>> $array_ref[$i]|;
>>> ...
>>> }
>>>
>>> Code works, but I'd much rather be able to pull native files straight out
>>> of the .zip, and change them that way... :P
>>>
>>> Anyway, again, if there are specifics I missed, happy to provide them.
>>> I keep thinking there should be an easy way to do this... but my
>>> google-fu is failing me..
>>>
>>> Thanks again for the help with the previous problem, and in advance for
>>> any assistance on this one.  :)
>>> At the very least, I guess I can provide some chatter to the group.
>>>
>>> -John (sephtin @gmail)
>>>
>>> _______________________________________________
>>> Raleigh-talk mailing list
>>> Raleigh-talk at pm.org
>>> http://mail.pm.org/mailman/listinfo/raleigh-talk
>>>
>>>
>>
>
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