Perl syntax

[Anthony]

It is very important that you understand exactly what
it is you are doing to fix the errors. Someone said
just put 

my $var="data"; 

 True it does stop the error messages but unless you
understand the correct scoping in the variables, your
program will have a lot worse logic problems down the
road.

You have to ensure your variables are scoped properly.
For example, when you:
use strict;

You must ensure to declare whether your variables are
dynmaically or lexically scoped.
Therefore you cannot declare a variable like this:

$var="data";

You have to tell the Perl interpreter in which blocks
the variables are valid.

my $var="data";

in the main prgram will ensure that $var is always
valid in the program. If it is placed inside its' own
block, $var will be valid inside that block, for
instance a subroutine. This allows you to reuse
variables. so $var can be different inside different
blocks.

Additional you can set a variable to only be valid
from the declaration until the end of the block.

Hope that helps.

Anthony
--- John Wildberger <wildberger-iRg7kjdsKiH3fQ9qLvQP4Q at public.gmane.org> wrote:
> In the recent thread on this subject the 'use
> strict' pragma was very strongly 
> suggessted.
> Here is a very simple program urc2_1.pl:
> 
> #! /usr/bin/perl -w
> use strict;
> while (<>){
>     $count{$ARGV}++;
> }
> foreach $file (sort keys %count){   
>     print "$file has $count{$file}  lines\n";
> }   
> 
> When executed it gives the following error messages:
> 
> [john]: 09:46 AM  [~/perl]
> $ ./urc2_1.pl urc2_1.pl
> Global symbol "%count" requires explicit package
> name at ./urc2_1.pl line 4.
> Global symbol "$file" requires explicit package name
> at ./urc2_1.pl line 6.
> Global symbol "%count" requires explicit package
> name at ./urc2_1.pl line 6.
> Global symbol "$file" requires explicit package name
> at ./urc2_1.pl line 7.
> Global symbol "%count" requires explicit package
> name at ./urc2_1.pl line 7.
> Global symbol "$file" requires explicit package name
> at ./urc2_1.pl line 7.
> Execution of ./urc2_1.pl aborted due to compilation
> errors.
> 
> Without the 'use strict' pragma it executes without
> errors like this:
> 
> [john]: 09:44 AM  [~/perl]
> $ ./urc2_1.pl urc2_1.pl
> urc2_1.pl has 9  lines
> 
> What changes to the program will I have to make to
> correct this?
> John
> --
> The Toronto Linux Users Group.      Meetings:
> http://tlug.ss.org
> TLUG requests: Linux topics, No HTML, wrap text
> below 80 columns
> How to UNSUBSCRIBE:
> http://tlug.ss.org/subscribe.shtml
> 
--
The Toronto Linux Users Group.      Meetings: http://tlug.ss.org
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://tlug.ss.org/subscribe.shtml