The $a have any special meanning ?

[sonet]

1.pl
----------------------
use strict;
$a=1;

the perl does not return error (Global symbol "$a" requires explicit package
name...)

but

2.pl

 

[Peter Wyzl]

1.pl
----------------------
use strict;
$a=1;

the perl does not return error (Global symbol "$a" requires explicit
package name...)

but

2.pl
----------------------
use strict;
$c=1;

the perl return error (Global symbol "$c" requires explicit package
name...)

$a and $b are special reserved variables used in sorting. perldoc -f sort

You can use them, but it is not good practice.

In fact single letter variable names are rarely good practice, particularly
when you need to re-edit that code in a years time...

P

 

[Tad McClellan]

Are you sure? I found examples in perldoc -f sort but these are examples.
Nowhere is mentioned about $a as special variable. In perlvar are mentioned
variables where second (third) character is not alphabetic, for example $`,
$/ etc. and only few alphabetic variables as @ARGV, @INC etc.

From perlvar.pod:

=item $a

=item $b

Special package variables when using sort(), see L<perlfunc/sort>.
Because of this specialness $a and $b don't need to be declared
(using use vars, or our()) even when using the C<strict 'vars'> pragma.
Don't lexicalize them with C<my $a> or C<my $b> if you want to be
able to use them in the sort() comparison block or function.

 

[Tad McClellan]

What version of Perl are you using?

5.8.8


I use 5.6.1

A lot has happened in the last 6 years.

Maybe this was be changed in 5.8.x ?

If you use ancient software, you should expect to miss out on a lot.

 

[Peter J. Holzer]

heh, I expected this ;-)

Yes, I know but Perl 5.8.0 looked as any version of Windows - it is stable
and usable 2-3 years after releasing Windows98 was be usable in year
2000, WinXP was be usable in year 2005, Windows Vista will be usable in year
2009? And Perl 5.8.x ? Yes, version 5.8.8 is usable with small problems and
version 5.8.10 will be stable as 5.6.1 is now

Huh? Software doesn't get more usable just with time. It needs to be
fixed. perl 5.6.1 hasn't seen any fixes in the last 6 years and was
released only one year after 5.6.0, so it can't be usable by your own
definition. The perl 5.8.x series OTOH is now 5 years old and should
have reached usable status per your "2-3 years" definition with release
5.8.5.

Perl 5.6.x is actually getting less usable as module authors stop
worrying about compatibility with it.

hp