#!/usr/bin/perl
# nlexample.plx
# The script opens a text file, reads it, prints a number and
# then each line within the file.
use warnings;
use strict;
use diagnostics;

open FILE, 'C:\Perl\Perl practice\test.txt' or die $!;
my $lineno = 1;

while(<FILE>)
{
   print $lineno++;
   print ": $_";
}
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One day you're going to have to face
   A deep dark truthfull terror,
And it's gonna tell you things that I still
   Love you too much to say.
####### Elvis Costello, Spike, 1988 #######

1:One day you're going to have to face
2:   A deep dark truthfull terror,
3:And it's gonna tell you things that I still
4:   Love you too much to say.
5:####### Elvis Costello, Spike, 1988 #######

Problem:

I using DzSoft Perl Editor to write my dode, and running from by the DOS promted provided by the IDE.

Uncaught exception from user code:
No such file or directory at C:\DOCUMENTS AND SETTINGS\RICHARD LAMB \L
+OCAL SETTINGS\Temp\dir11.tmp\nlexample.plx line 8
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Solution: Locating the test.txt file in local settings?

edited: Thu Jul 24 00:37:03 2003 by jeffa - code tags formatting

I'm just guessing (never heard of "DzSoft Perl Editor"), but if this happens to be "line 8" of your test script:

open FILE, 'C:\Perl\Perl practice\test.txt' or die $!;
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then the error report would have something to do with the "open" statement and the file name string that you're giving it.

If the perl interpreter (perl.exe) is in a directory that's covered by your PATH environment variable in a DOS shell, try stepping away from the DzSoft IDE for a bit, and use the shell. Go to the directory where your test perl script is kept, and do:

  perl  name_of_test_script
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If it gives a similar error report, try using forward slashes "/" instead of backslashes "\" in the file name that you pass to "open()". (I did say I was guessing...) Then make sure that the "test.txt" file really does exist in that exact path.

Just out of curiosity, what do you get when you run this command in a DOS shell:

perl -V
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For that matter, if you went to a directory that contains some longer file names (and names with spaces in them, etc), what would you get if you try this command:

perl -e 'opendir(D,"."); print join($/,readdir(D)),$/'
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Do all the complete file names show up (long, with spaces,etc)? How about when you run that one-liner from within the IDE?

One other point: don't even think about trying to do regex substitutions on HTML text data for the sake of "expanding" visible white-space. It'll give you a headache. Doing it without HTML::TokeParser would be utterly wrong. Doing it with HTML::TokeParser (and, say, adding   in strategic spots) would just be misguided and unsatisfying (you'd see some results, but you'd rarely see results that look good).

Thanks very much for the advice! I'm no longer an 'opening files for reading' virgin. I rechecked the file path, and gotten it wrong. Doh. It's solved now, thankfully. Next problem is to extract an image html tag from the file that i'm reading and print it out (sent that question today). After that, I'll need to write to the html file. Starting to find the hacking a lot of fun... Cheers, Richard

Graff, Cheers for the pointers. I've opened my HTML test file, written regexps to remove image and anchor tags, and printed them out. Need to write these mods to the original file, then refresh the HTML page - Happy Days! My supervisor mentioned the that regexps may have limitations, so i'm beginning to look into the HTML parse-tree approach (is that the same approach you recommende?). Here's the source code i've put together so far! Rich

#!/usr/bin/perl
# remove img & anchor tags.plx
# Program will read in an html file, remove the img tag and print out 
+entire doc.
# 1. No need for file variable yet: open (INFILE, "<".$htmlFile) or di
+e("Can't read source file!\n");
# 2. Alternative: m/<A\s+HREF=[^>]+>(.*?)<\/A>/  - Will not remove clo
+sing tag though - why?
# 3. Why is interpreter flipping-out over an 'undefined variable', whe
+n
#    original regexp, m/<A\s+HREF=[^>]+>(.*?)<\/A>/, is known to work.
+ What am I missing?

use warnings;
use diagnostics;
use strict;
use HTML::Parser;    # Include this module for future reference - may 
+need to abandon
                     # regexps in favour of parse-trees.

# Declare and initialise variables.
my $pattern1 = '<IMG\s+(.*)>';
my $pattern2 = '<A\s+HREF\s*=[^>]+>';
my $pattern3 = '</A>';
my @htmlLines;

# Open HTML test file and read into array.
open INFILE, "E:\\Documents and Settings\\Richard Lamb\\My Documents\\
+HTMLworkspace\\HTML practice\\My First Page!\\firsttest.html" or die 
+"Sod! Can't open this file.\n";
@htmlLines = <INFILE>;
close (INFILE);

# Test for presence of patterns in HTML file
if($pattern1)
{
  scrapImageTag(); # calls to remove image tags
}
else
{
  print "No tags matching this pattern within the HTML document.\n";
}

if($pattern2 && $pattern3)
{
  scrapAnchorTag();
}
else
{
  print "No tags matching this pattern within the HTML document.\n";
}

# Removes image tag elements in array
sub scrapImageTag
{
  foreach my $line (@htmlLines)
  {
    # replace <IMG ...> with nothing.
    $line =~ s/$pattern1//ig;  # case insensitivity and global search 
+for pattern
  }
}

# Removes anchor tag elements in array
sub scrapAnchorTag
{
  foreach my $line (@htmlLines)
  {
    # replace <A HREF ...> with nothing.
    $line =~ s/$pattern2//ig;  # case insensitivity and global search 
+for pattern
    $line =~ s/$pattern3//ig;  # case insensitivity and global search 
+for pattern
  }
}

printHTML();

# prints the reformatted HTML doc
sub printHTML
{
  for my $i (0..@htmlLines-1)
  {
    print $htmlLines[$i];
  }
}

print "\n\n";
sleep 2;
print "Success?!\n";
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