On Thu, Sep 04, 2003 at 01:32:57AM -0400, Guy Albertelli II wrote:
> Dosen't seem to bleed default_root or default_share, and the bleed of
> things other than expr is a perl 5.8.1 ism:
> 
> Test script:
> use strict;
> use Safe;
> print $]."\n";
> my $safe=new Safe;
> 
> foreach my $name ('default_root','default_share','expr','obj','strict','root','evalcode','evalsub') {
>     print("Test $name is :".$safe->reval('return $'.$name.';').":\n");
> }
> 
> 
> 5.008001
> Test default_root is ::
> Test default_share is ::
> Test expr is :return $expr;:
> Test obj is :Safe=HASH(0x9f2bd28):
> Test strict is ::
> Test root is :Safe::Root0:
> Test evalcode is :package Safe::Root0; sub { @_ = (); eval $expr; }:
> Test evalsub is :CODE(0x9f45d0c):
> 
> 5.008
> Test default_root is ::
> Test default_share is ::
> Test expr is :return $expr;:
> Test obj is ::
> Test strict is ::
> Test root is ::
> Test evalcode is ::
> Test evalsub is ::
> 
> 5.006001
> Test default_root is ::
> Test default_share is ::
> Test expr is :return $expr;:
> Test obj is ::
> Test strict is ::
> Test root is ::
> Test evalcode is ::
> Test evalsub is ::

This is because 5.8.1 includes fixes that allow nested evals to still see
their full lexical scope.

As of 5.8.1, to code to be eval'ed will be able to see:

* any lexical vars declared above it but within reval();
* any lexical vars declared above reval(), but which are referred to
  within reval() - ie reval() acting as a closure. Currently there are no
  such variables.
Any other lexicals will have gone out of scope by then, and any attempt to
use them within an eval will give a '$foo is not available' warning.

Having said that, I think Benjamin's suggestion of having an eval function
at the very start of the script before any lexicals of any description
have been declared, is a sensible idea. It will help protect us against
any future changes to the code that inadvertently create a closure.

Dave.

-- 
"Foul and greedy Dwarf - you have eaten the last candle."
    - "Hoardes of the Things", BBC Radio.