in reply to Re: substuting a whole file
in thread substuting a whole file

UPDATE: I have to agree with the rest of them. For safety reasons (so you don't demolish the test file), you may want to open $file but save to $file2 just incase the unexpected happens..

I have a few questions or comments about the script you wrote. How exactly isn't this going to treat HTML correctly? All you're doing is taking any text it finds, regardless of what characters it is, and try to put it into lowercase. You're not treating HTML, you're treating text. I tested your script out with <A HREF= in the @codes and it worked fine. It's not interpreting the file as HTML at all, so no matter what you throw in there (thanks to quotemeta), it'll do it's job.

My question to you was, what exactly is line 5 doing with the joining, maping and sorting? You're playing with length which I thought only stored the length in characters of the item you're using it with.



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Re: Re: Re: substuting a whole file
by ysth (Canon) on Jan 14, 2004 at 19:59 UTC
    UPDATE: I have to agree with the rest of them. For safety reasons (so you don't demolish the test file), you may want to open $file but save to $file2 just incase the unexpected happens..
    I agree, and will update my node to do so.
    How exactly isn't this going to treat HTML correctly? ... It's not interpreting the file as HTML at all
    That's all I meant; it won't look for HTML tags, it will look for literal text, including what it finds in comments, script, etc.
    My question to you was, what exactly is line 5 doing with the joining, maping and sorting? You're playing with length which I thought only stored the length in characters of the item you're using it with.
    Sorting greatest length first ensures that the match will work if you have e.g. "<A " and "<A HREF". Without the sort, you get results like: 
    $ perl
use warnings;
use strict;

my @codes = ("<a ", "<a href");
my $codes_regex = join "|", map quotemeta $_,
# sort { length $b <=> length $a }
                                   @codes;
my $text = "testing a link: <A HREF=\"fooble.html\">boofle</a>";
print "in:  $text\n";
$text =~ s/($codes_regex)/lc $1/gie;
print "out: $text\n";
__END__

output with the sort:
in:  testing a link: <A HREF="fooble.html">boofle</a>
out: testing a link: <a href="fooble.html">boofle</a>

and without:
in:  testing a link: <A HREF="fooble.html">boofle</a>
out: testing a link: <a HREF="fooble.html">boofle</a>

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    This is because the perl regexes prefer the leftmost |'d alternative, even if it makes a shorter match.

    The map is just to apply the quotemeta; the join is to put | between tags.

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