How can an external injected global variable be accessed simply by its name?

That snippet does not work without fully qualifying the variable:

#! /bin/perl

use strict; use warnings;

package Haus;

sub test{
        print __PACKAGE__."\n";

        # Works
        print "qualified var [$Haus::var]\n"; # OK

        # not working, why and how to achieve that without
        # local "our $var" instead external injected
        print "simple var [$var]\n"; # NOK
}

package main;

$Haus::var=1;
Haus::test();

CodePudding user response：

You (appropriately) asked Perl to not let you use $var without first declaring $var.

strict vars

This generates a compile-time error if you access a variable that was neither explicitly declared (using any of my, our, state, or use vars) nor fully qualified. (Because this is to avoid variable suicide problems and subtle dynamic scoping issues, a merely local variable isn't good enough.) See "my" in perlfunc, "our" in perlfunc, "state" in perlfunc, "local" in perlfunc, and vars.

All you need to do is declare $var. Both our $var; and use vars qw( $var ); would do the trick here.

You could also remove the request (by using use strict; no strict qw( vars );), but there's no reason to do that, and plenty not to.

CodePudding user response：

I think, that you got a compile time error because stricture is enabled and $var is not declared in your example. Declare the variable with our so that Perl knows that you mean $Haus::var. See our