Re: safe and $self

From the Safe docs for share(NAME, ...): Each NAME must be the name of a non-lexical variable, typically with the leading type identifier included.

Since in OO Perl the current instance of a package is referred to merely by a lexical variable declared within a subroutine, i.e., my $this = shift(@_), sharing it will not be possible. You're seeing 'uninitialized' warnings now because Safe attempts to look up $SamplePackage::self, which is uninitialized.

If you're truly desperate you could effectively make your class instance a public static member using our, and then share that reference. But that's generally a bad idea unless you're sure your instance will always be a singleton.

Comment on Re: safe and $self Select or Download Code

Replies are listed 'Best First'.
Re: Re: safe and $self by feanor_269 (Beadle) on Nov 26, 2002 at 23:11 UTC
I finally signed up for an account (instead of just lurking), so I'm the anonymous monk that posted this node. the code I have is: `sub codewrapper { my $self = shift; $self->{code}->share('$self'); $self->{code}->share('$test'); $code=$_[0]; $self->{code}->reval($code); $test->{code}->reval($code); }` [download] $test is the test object, and that gives the same error, it is declared with my $test = ..., but outside of any subs. neither work, both produce eval errors.	[reply] [d/l]
Re: Re: Re: safe and $self by djantzen (Priest) on Nov 27, 2002 at 02:09 UTC
So I take it `$self->{code}` contains a reference to an instance of Safe. Again, if `$test` is declared using my, it is a lexical variable and hence cannot be shared with the code inside of the compartment. See these nodes for more on dynamic versus lexical variables: What's the difference between dynamic and lexical (static) scoping? Between local() and my()? and Lexical vs. Package Variables (With a little local thrown in).	[reply] [d/l] [select]
Re^3: safe and $self by tadman (Prior) on Nov 27, 2002 at 05:57 UTC
I think, like what fever said, that you've painted yourself in to a corner with this. `$self` is a lexical variable, in other words, it doesn't really exist outside of the `codewrapper` function, those seven lines. The real problem is if you are ever calling the `codewrapper` function within itself. Then you're going to have trouble sharing the correct `$self` since there will, at that point, be two of them. The solution might be to not use Safe at all. It might be best to re-engineer your application, since using eval, and presumably `reval` are much slower than the alternatives. If this isn't going to work, then what you're probably going to have to do is create separate compartments for each object. I'm not sure if there's an easy way to do this or not.	[reply] [d/l] [select]
Re: Re^3: safe and $self by feanor_269 (Beadle) on Nov 27, 2002 at 17:52 UTC
Unfortunately, since I have to eval perl code from untrusted sources (this would be for a mud, and they would be the builders and imms... see what I mean by untrustworthy?) I have to use safe and reval. speed isn't horribly important either. I'm going to play with making an array of the references to each object and just sharing that locally (Altho maybe just as a package variable?) anyway, class, no time now.	[reply]