Perl syntax

[Anthony]

Missed a line.

To declare a variable to only be valid from
declaration to the end of the block use.

local $var="data;

Anthony
--- Anthony <agamemnon67-bJEeYj9oJeDQT0dZR+AlfA at public.gmane.org> wrote:
> 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
> > --
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--
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