Control flow question

Tricky has asked for the wisdom of the Perl Monks concerning the following question:

Hi folks,

Many thanks for the help recently. I have another query for the Wise. Here's a brief explanation of my code, which you'll find below. I'm opening an HTML file on my hard-drive, slurping it into an array (if jeffa's out there, I've adopted the approach as suggested, but I'm just playing with this for the time being - going to a similar control loop later), then testing for the presence (or lack) of word spacing attributes within in-line styles.

If the pattern doesn't match, the attribute is added to certain in-line styles (header, paragraph and list tags). The document is then printed on-screen. Otherwise, a warning is printed instead

The code seems to work, but an error message appears. Here goes:

Use of unitialized value in array element at controlflow.plx
 (#1) line 21
(W uninitialized) An undefined value was used as if it were 
already defined. It was interpreted as a "" or a 0, but maybe it was a
+ mistake. To suppress this warning assign a defined value to your var
+iables.
[download]

I'm doing something very obvious, bu cannot see it, aint I? Here's the code:

#!/usr/bin/perl
# controlflow.plx

=head1 DESCRIPTION
Program will read in an html file and add word spacing style attribute
+s to header, paragraph and list tags.
and print out doc in DOS window. Presence of tags/attributes will be t
+ested for via an 'if-else'
control structure.
=head2 ALTERNATIVE FILE OPENING CODE
$htmlFile = "E:/Documents and Settings/Richard Lamb/My Documents/HTML/
+dummy.html";
open (INFILE, "<".$htmlFile) or die("$!: Can't read source file!\n");
=cut

use warnings;
use diagnostics;
use strict;

# Declare and initialise variables.
my @htmlLines;

# Open HTML test file and read into array.
open (INFILE, "E:/Documents and Settings/Richard Lamb/My Documents/HTM
+L/dummy.html"), or die ("$!: Can't open this file.\n");
@htmlLines = <INFILE>;
close (INFILE);
# Check for attribute pattern in file
if($htmlLines[my $i] !~ m/word-spacing:\s?[\d]+px/ig)
{ # Loop through file stored in array, inserting attribute
  foreach my $line (@htmlLines)
  {
    $line =~ s/(<h[1-6]\sstyle=.*)">/$1; word-spacing: 30px">/ig;  # c
+ase insensitivity and global search for pattern.
    $line =~ s/(<p\sstyle=.*)">/$1; word-spacing: 10px">/ig;
    $line =~ s/(<li\sstyle=.*)">/$1; word-spacing: 10px">/ig;
  }
  # Print modified file in DOS window
  for my $i (0..@htmlLines-1)
  {
    print $htmlLines[$i];
  }
}
else
{
  print "Attribute not in HTML file\n";
}
[download]

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Re: Control flow question by Abigail-II (Bishop) on Sep 05, 2003 at 12:14 UTC
I'm doing something very obvious, bu cannot see it, aint I? Here's the code: You know, if you get a warning or an error message with a line number, and ask about it, don't just post a blob of code, also indicate which line the warning is about. Now you've already gotten two replies, and both replies guess a different line where the error might be. At least one of the answers is about the wrong line. Number your lines, or place a comment in the code "this is line 21". A little courtesy towards the people answering is welcome. Abigail	[reply]
Re: Re: Control flow question by Tricky (Sexton) on Sep 05, 2003 at 12:30 UTC
My apologies. Thanks for tip. The modified code will be sent forthwith. Regards Richard	[reply]
Re: Control flow question by Aragorn (Curate) on Sep 05, 2003 at 11:59 UTC
I don't think you can declare (with `my`) a variable in an array lookup. I think you messed up the looping through the array with HTML lines. In the `if($htmlLines[my $i] !~ m/word-spacing:\s?[\d]+px/ig)` [download] line, what value do you expect `$i` to have? Arjen	[reply] [d/l] [select]
Re: Control flow question by liz (Monsignor) on Sep 05, 2003 at 11:53 UTC
I think you want to lose the comma in: `open (INFILE, "E:/Documents and Settings/Richard Lamb/My Documents/HTM +L/dummy.html") or die ("$!: Can't open this file.\n"); + ^` [download] Liz	[reply] [d/l]
Re: Control flow question by CountZero (Bishop) on Sep 05, 2003 at 13:05 UTC
Your code works without errors or warnings on my Activestate Perl 5.6.1 with all warnings enabled. CountZero "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law	[reply]