On Wed, 2003-09-03 at 21:24, Stas Bekman wrote:
> [...]
> >>In effect you use local() to undef the variable, instead of explicitly
> >>initializing it. Why not doing this explictly?
> >
> >
> > Firstly it's conceptually neater to use local. I want to think of the
> > variable as local rather than as a global variable that needs to be
> > explicitly reset.
>
> local is perl4-ism, nowadays it's used only for localizing special perl
> variables, like $|.
I agree, using local, and especially "local our" is pretty strange. It
may work, but I wouldn't want to encourage people to do that in their
code.
> To summarize:
>
> - move the perl4 lib solution to the perl_reference.pod
> - suggest replacing my() with our() to avoid the closure, however this change
> requires that the variables will be initialized before used in most cases
> (example of 'open our $foo' which doesn't need to be initialized). you can
> initialize variables by an explicit assignment of the value, or using the
> 'local our' trick, which will initialize the variable to under, which is
> probably not what you want.
> - for users of perl < 5.6 suggest to use 'use vars' instead of 'our'.
> - point to perl_reference.pod for other workarounds/solutions.
May I also suggest telling users to pass arguments explicitly to subs,
instead of doing it implicitly? Nearly all of the Registry-related bugs
I see stem from people doing this:
my $cgi = CGI->new();
foo()
sub foo {
$cgi->param(whatever)...
}
They accidentally create a closure this way and then wonder why their
form values never change. Passing $cgi to foo() fixes the problem.
- Perrin
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