Re: Whether to use local()

[PrakashK]

in reply to Whether to use local()

My question is whether you should be concerned with scope if $new_mail needs to be shared between sub update_mail_list and sub read_mail_list etc.

One trick I sometimes use to share a variable among multiple subroutines, without making it a package variable is to enclose all of them in a block.

{
    my $new_mail;

    sub update_mail_list
    {
        # uses $new_mail
    }

    sub read_mail_list
    {
        # uses $new_mail
    }
}

What do monks think about this style?

Thanks,
/prakash

[grinder]

I was wondering if someone was going to bring this up. To me, this is the best way to share a variable between two (or more) subroutines.

Just bear in mind, though, that you may receive puzzling errors regarding $new_mail being undefined, depending on where this code appears in the file, and how and when control gets passed to update_mail_list() or read_mail_list().

Best practices would suggest that rathing than enclosing the variable and the referring subs in bare { } braces, you should use a BEGIN { } block. This will ensure that $new_mail gets set up on the lexical pad before you get around to using it.


print@_{sort keys %_},$/if%_=split//,'= & *a?b:e\f/h^h!j+n,o@o;r$s-t%t#u'

[tilly]

I use this as well.

But don't if you are going anywhere near mod_perl. Else much grief awaits you...

[runrig]

That should only be a problem if you do that in an Apache::Registry script (and any similar beasts, if they exist). If its in a module use'd by an A::R script (and maybe even in a non A::R handler?), it should be ok (if I'm not mistaken, and if you're careful).