While experimenting with this code I stepped away from using $a, main and one-liners and I can report to you that the results are exactly the same:

package Foo ;
use strict ;
our $t = 2 ;
{
    BEGIN {
        # package Bar ; # added
        *Foo::x = \$Foo::t;
    }
    ++$x ;
    # ++$Foo::x; # no errors
    print $x ;
    # print $Foo::x; # no errors
}

[download]

Small note regards the Deparse results: With 'package Bar' disabled it looks like *Foo::x = \$Foo::t; becomes: *x = \$t; and with 'package Bar' enabled it becomes: *Foo::x = \$Foo::t;. Inside the BEGIN statement I think it is likely that the first form is not a valid trigger to 'declare' $x and the latter form is valid, but the reason could also be what tye said regards: "when the variable slot of a glob gets assigned to by code compiled into another package". But I am still confused though 'what' declared means. Is it turned into a lexical scoped package variable, or is it similar to 'use vars'?. This line in 'use' documentation is not clear to me:"...which are effective through the end of the file..." in the text: "Some of these pseudo-modules import semantics into the current block scope (like strict or integer , unlike ordinary modules, which import symbols into the current package (which are effective through the end of the file)".

In case you do wish to use this as a one-liner (Windows):

perl -MO=Deparse -wMstrict -e "package Foo ; our $t = 2 ; { BEGIN { package Bar { *Foo::x=\$Foo::t } } ; ++$x ; print $x }"

In reply to Re^3: Logic for importing and strict vars? by Veltro
in thread Logic for importing and strict vars? by haukex

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