http://www.perlmonks.org?node_id=991511


in reply to Re^6: dynamic loading modules
in thread dynamic loading modules

Perhaps you should have a look at the source of File::Spec. Or perhaps not. Think about the following construct first:

(Each code block represents a properly named file)

package MyProject::OSSpecific::base; use strict; use warnings; sub niceOSName { my $class=shift; die "$class does not implement an OS specific niceOSName() method" +; } sub tempDir { die "I don't know how to find a temp directory"; } sub pathSep { return '/'; } sub installTo { die "Should not happen"; } # much more methods 1;
package MyProject::OSSpecific::doslike; use strict; use warnings; use parent 'MyProject::OSSpecific::base'; sub tempDir { return 'c:\\temp'; } sub pathSep { return '\\'; } # much more methods 1;
package MyProject::OSSpecific::dos; use strict; use warnings; use parent 'MyProject::OSSpecific::doslike'; use Some::DOS::Specific::Module; sub niceOSName { my $x=`command /c ver`; chomp $x; return $x; } sub installTo { return 'C:\myproject'; } 1;
package MyProject::OSSpecific::MSWin32; use strict; use warnings; use parent 'MyProject::OSSpecific::doslike'; use Win32; sub niceOSName { return Win32::GetOSName(); } sub installTo { return 'C:\\Program Files\\MyProject'; } 1;
package MyProject::OSSpecific::unixlike; use strict; use warnings; use parent 'MyProject::OSSpecific::base'; sub niceOSName { my $x=`uname -a`; chomp $x; return $x; } sub tempDir { return '/tmp'; } sub pathSep { return '/'; } # much more methods 1;
package MyProject::OSSpecific::freebsd; use strict; use warnings; use parent 'MyProject::OSSpecific::unixlike'; use Something::Created::Only::For::FreeBSD; sub installTo { return '/usr/local/myproject'; } 1;
package MyProject::OSSpecific::linux; use strict; use warnings; use parent 'MyProject::OSSpecific::unixlike'; use Something::Very::Linux::Specific; sub installTo { return '/opt/myproject'; } 1;
And finally:
packame MyProject::OSSpecific; use strict; use warnings; use parent 'MyProject::OSSpecific::'.$^O; # <-- this is the most impor +tant trick here. 1;
In your code:
use strict; use warnings; use MyProject::OSSpecific; print "This program should be installed to ",MyProject::OSSpecific->in +stallTo(),"\n";

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)