Re^4: Strict isn't strict enough

[davies]

what should perl do if you did my $hwatever and then cut-and-pasted the $hwatever?

Give a compile time error when I use $whatever. Obviously it isn't a problem if the same typo is used throughout, but if a variable can be used in two places then there is scope for typos that I expected strict to catch before I read the docs. I still want to catch it if I can.

Regards,

John Davies

[JavaFan]

So, what should happen at:

package Foo;

declare $slave::whatever;  # Inventing a keyword to declare fully qual
+ified names.

$slave::whatever = 1;

__END__

package Bar;

declare $slave::hwatever;

print $slave::hwatever;

__END__

Typo, or intentional?

[davies]

It must depend on declare's documented behaviour.

I think you're trying to have a Socratic dialogue with me, for which I'm grateful, but I'm not clear where it's leading, meaning that my confusion is increasing. Tye has given me a workaround, but no-one has answered outright my original question "Is there anything that will report the use of undeclared fully qualified variable names?". From the help I have received, I'm pretty sure that the answer is "no". I'm used to having to use fully qualified names to avoid "Bill Gates knows best" problems, so I was not expecting the behaviour I experienced until I read the docs, and I was expecting it to be the sort of issue that had been resolved by others. If (as seems to be the case) not, I shall have different expectations in future. But as I say, I'm not certain where this is leading. If it's somewhere useful, I shall be duly grateful.

Regards,

John Davies

Update: fixed minor typo

[BrowserUk]

The simple fact is that not only do you not have to declare global variables -- "fully qualified variable names" are always globals --, you cannot declare them. Perl has no mechanism for doing that.

You seem to be equating the action of our with that of my, but they are in not equivalent. my actually creates new variables, but our simply allows you silent, unqualified access to them in the current lexical scope.

One possibility that might in some way meet your requirement would be to use Hash::Util::lock_keys() to restrict the package hash to just those keys you require.

Update: A little explanation of the idea:

use Hash::Util qw[ lock_keys ];;

$My::Space::fred = 12345;;
%My::Space::hash = 1 .. 10;;
@My::Space::array = 1 .. 10;;

lock_keys( %My::Space:: );;

print $My::Space::fred;;
12345

print $My::Space::fred = 23456;;
23456

print $My::Space::fred;;
23456

print $My::Space::freddy = 1234;;
Attempt to access disallowed key 'freddy' in a restricted hash at (eva
+l 18) line 1, <STDIN> line 10.