http://www.perlmonks.org?node_id=305319


in reply to module location

"use" happens at compile time, but the $perl_module variable isn't initialized until run time, after the "use" statement has already executed. Actually you can't use a variable package name, but you can require it. Try this:

#!/usr/bin/perl -w
use strict;
my $perl_module = shift;
eval {require $perl_module} or die "Can't find $perl_module!";

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Alan

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Re: Re: module location
by hmerrill (Friar) on Nov 07, 2003 at 15:34 UTC
    I thought you had it, but not I get this error: 
       Can't find DBI! at ./test.pl line 4.

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    Here is the absolute path to the DBI.pm file: 
       /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi/DBI.pm

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    and the @INC path shows this in 'perl -V': 
      @INC:
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.0
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.0
    /usr/lib/perl5/vendor_perl
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0

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    What am I missing? Thanks for your help!
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      Well, there are a few solutions to this.

      My bug was: require DBI looks for "DBI.pm" because DBI is a bareword; but this does not work if you put the bareword in a variable and require that instead.

      One simple solution is to just:

      ./test.pl DBI.pm

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      If you don't like that, you can change the eval to a string eval, which will interpolate the package name into a bareword before require sees it:

      #!/usr/bin/perl -w
use strict;
my $perl_module = shift;
eval "require $perl_module" or die "Can't find $perl_module!";

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      This would be the more flexible solution, since it would handle things like ./test.pl DBD::PgSQL (assuming that makes sense... basically, any module with ::'s in it).

      Alan

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