Using Strick in PERL

[yjulien]

Hi,

Why is it that if I use "strict" in Perl, I can no longer use any variable as I wish?

Let me explain with this simple script.

#!/usr/local/bin/perl

print "Content-type: text/html\n\n";

$path = "/usr/www/users/yjulien/voile/cgi-bin/calcule_energie";

print $path

exit;

If I run the script I get this output:

/usr/www/users/yjulien/voile/cgi-bin/calcule_energie


But if I ad "use script;" like this:

#!/usr/local/bin/perl

use strict;

print "Content-type: text/html\n\n";

$path = "/usr/www/users/yjulien/voile/cgi-bin/calcule_energie";

print $path

exit;

I get an "Internal Server Error" message.

Where is the conflict?

Thanks,

Yves

[RonB]

The strict pragma requires you to declare your vars before they are used. They can be declared as a global var by using the 'our' keyword or by using the 'my' keyword which creates lexical var and limits their scope to the enclosing block. 99.90% of the time you should use 'my' to create a lexical var.

Declaring your var limits its scope. You should limit your vars to the smallest scope that they require.

[yjulien]

Thanks Ron,

My problem is that I don't know how to use it properly.

For instance, I have this code that pull the current path of my directory. It works if I don't use strict:

unless ($path) {

$path = $0;
$path =~ s/\\\\/\\/g;
$path =~ s/\\/\//g;
$path =~ s/(\/)(\w*)(\.*)(\w+)$//g;

unless ($path =~ /\//) {
if ($os eq "unix") { $path = `pwd`; }
}

unless ($path =~ /\//) {
$path = $ENV{'SCRIPT_FILENAME'};
$path =~ s/\\\\/\\/g;
$path =~ s/\\/\//g;
$path =~ s/(\/)(\w*)(\.*)(\w+)$//g;
}

$path =~ s/ //g;
$path =~ s/\n//g;

unless ($path =~ /\//) { &path_error; }

}

If I want to use strict, how do I use "my" or "our"?

I tried with starting the routine with a simple "my $path = ""; but it dod not worl :-(

Thanks for your help,

Yves

[RonB]

my $path;

unless ($path) {
 
$path = $0;
$path =~ s/\\\\/\\/g;
$path =~ s/\\/\//g;
$path =~ s/(\/)(\w*)(\.*)(\w+)$//g;
 
unless ($path =~ /\//) {
if ($os eq "unix") { $path = `pwd`; }
}
 
unless ($path =~ /\//) {
$path = $ENV{'SCRIPT_FILENAME'};
$path =~ s/\\\\/\\/g;
$path =~ s/\\/\//g;
$path =~ s/(\/)(\w*)(\.*)(\w+)$//g;
}
 
$path =~ s/ //g;
$path =~ s/\n//g;
 
unless ($path =~ /\//) { &path_error; }
 
}

FYI, there are far easier ways to get the path.

http://search.cpan.org/~smueller/PathTools-3.40/Cwd.pm

http://search.cpan.org/~rjbs/perl-5.18.1/lib/File/Basename.pm

[yjulien]

FYI, there are far easier ways to get the path.

http://search.cpan.org/~smueller/PathTools-3.40/Cwd.pm

http://search.cpan.org/~rjbs/perl-5....le/Basename.pm

Indeed thanks again !!!