Nathan Wiger <[EMAIL PROTECTED]> writes:
> > You've taken the wrong approach. If you're writing a big program then
> > there should be *no* default scope. Any variable access is an error
> > unless that variable was my()ed or our()ed. That's basically what
> > 'strict' gives us.
>
> Fair enough. I've heard several good analyses against my idea, so I'll
> fold. Notice I never claimed it was a *good* idea (hence the lack of
> RFC), but just an idea worth pondering.
>
> However, I do think there's something to be said for a "quick-and-dirty"
> script out of the box that can distinguish between sub{} vars and other
> vars ala C:
>
> $user = 'nwiger';
> sub whois {
> ($user) = @_; # different var
> # ...
> }
> print whois($user);
Uhmm, but now you've killed off *any* chance of whois (or any other
sub) *ever* setting $user -- the first time it tries to do that, it
gets a `different var' and the original remains unchanged.
In particular, one of Perl's greatest advantages over Python -- the
existence of real closures -- softly and silently vanishes away.
Consider this code (Perl/Tk code tends to be similar):
sub make_summer {
my $x = 0;
sub { $x += shift }
}
Then we can say:
DB<2> $a = make_summer
DB<3> $b = make_summer
DB<4> x $a->(2)
2
DB<5> x $a->(3)
5
DB<6> x $b->(11)
11
DB<7> x $b->(-1)
10
But it is impossible to write make_summer with your suggestions in
effect! Suddenly, the `$x' in the anonymous sub make_summer is trying
to create becomes a *new* variable, and all state goes away.
What you're proposing seems to be the abolition of *all* scopes from
Perl, except the innermost-sub scope. This is worse than Pascal.
But here's an idea: suppose you spelt `my' V-A-R. Then you could say
Perl is forcing you to declare all your variables (which I claim is
essential in a language with useful scopes). Of course, it's one
character longer, so I suppose `var' is out of the question...
[...]
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Ariel Scolnicov |"GCAAGAATTGAACTGTAG" | [EMAIL PROTECTED]
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