use lib between modules

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I'm sure there's an obvious answer to this, but I can't seem to find it. Suppose I have these files:

    /(lib path)/dirAAA/ModuleA.pm
    /(lib path)/dirBBB/ModuleB.pm
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where (lib path) will differ from one installation to another. Also for various reasons I can't put ModuleA and ModuleB in the same directory. ModuleA needs to use ModuleB. In ModuleA I put:

    use lib ???;
    use ModuleB;
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What do I use for ??? I know that these are no good: # WRONG: relative to caller who could be anywhere:

<code>
use lib '../dirAAA/'
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# WRONG: relative to calling script which could be anywhere:

use FindBin;
use lib "$FindBin::Bin/../dirAAA/"
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How do I specify 'relative to the current file (Module A)'? My apologies for posting anonymously; I'm having trouble logging in. thanks, David

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Re: use lib between modules by dragonchild (Archbishop) on Feb 14, 2005 at 19:07 UTC
Presumably, you've done a `use lib qw( /(lib path)/dirAAA );` somewhere prior to running the code in ModuleA, otherwise you wouldn't have gotten there. One, somewhat hackish, solution is to inspect @INC. `BEGIN { my $lib_to_use; foreach my $dir (@INC) { $lib_to_use = $dir, last if $dir =~ m!dirAAA/?$!; }; $lib_to_use =~ s!dirAAA!dirBBB!; use lib $lib_to_use; } use ModuleB;` [download] I'm sure there's a module that does this, but I'm too lazy to look for it. Being right, does not endow the right to be rude; politeness costs nothing. Being unknowing, is not the same as being stupid. Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence. Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.	[reply] [d/l] [select]
Re^2: use lib between modules by Anonymous Monk on Feb 15, 2005 at 15:38 UTC
Thanks dragonchild and Tanktalus. First, I'm relieved that I wasn't overlooking something obvious. Second, I'm surprised that there isn't a more straightforward way of doing this. But maybe that's not a bad thing. As you both pointed out, it's probably better if all the application specific modules reside in the same directory, if possible. Thanks again! -David	[reply]
Re: use lib between modules by Tanktalus (Canon) on Feb 14, 2005 at 19:07 UTC
In my ideal world, I'd have /(lib path) in the lib already, and then use dirAAA::ModuleA and dirBBB::ModuleB. Assuming, however, that you're really using "use ModuleA" to get at ModuleA, you can use %INC: `my $libpath; BEGIN { ($libpath = $INC{'ModuleA.pm'}) =~ s:/dirAAA/.*:dirBBB:; } use lib $libpath;` [download]	[reply] [d/l]