Re: How to avoid circular module dependencies within a distribution?

David Christensen:

> Here is a contrived example that shows circular modular dependency
> without circular subroutine dependency:

In this particular case, I'd move subs bar2 and foo2 to another
module FooBar.pm, and have Foo.pm and Bar.pm import those subs
from FooBar.pm instead:

> 2016-10-19 11:05:08 dpchrist@t7400 ~/sandbox/perl/circular-dependency
> $ cat Foo.pm
> package Foo;
> use strict;
> use warnings;
> require Exporter;
> our @ISA = qw( Exporter );
> our @EXPORT = qw( foo1 foo2 );
> use Bar;
> sub foo1 { print "foo1\n"; bar2(); }
> sub foo2 { print "foo2\n";         }

package Foo;
use strict;
use warnings;
require Exporter;
our @ISA = qw( Exporter );
our @EXPORT = qw( foo1 );
use FooBar;
sub foo1 { print "foo1\n"; bar2(); }

> 2016-10-19 11:05:10 dpchrist@t7400 ~/sandbox/perl/circular-dependency
> $ cat Bar.pm
> package Bar;
> use strict;
> use warnings;
> require Exporter;
> our @ISA = qw( Exporter );
> our @EXPORT = qw( bar1 bar2 );
> use Foo;
> sub bar1 { print "bar1\n"; foo2(); }
> sub bar2 { print "bar2\n";         }

package Bar;
use strict;
use warnings;
require Exporter;
our @ISA = qw( Exporter );
our @EXPORT = qw( bar1 );
use FooBar;
sub bar1 { print "bar1\n"; foo2(); }

# FooBar.pm
package FooBar;
use strict;
use warnings;
require Exporter;
our @ISA = qw( Exporter );
our @EXPORT = qw( foo2 bar2 );
sub foo2 { print "foo2\n"; }
sub bar2 { print "bar2\n"; }

Deciding if bar2 and foo2 will go together or separatedly depends
mostly on the problem at hand, so I'm suggesting the shortest
path (i.e. together) with the information I have.

Cheers,
Alex