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

Hello Monks,

I'm having an issue with one of my scripts where I try and require other Perl modules via eval 'require' using the -I flag and it fails, whereas it works via another eval 'require' in another script, where the includes directories are more hardcoded into the script.

Code:

Module Validator (simple): 
#======================
#BEGIN MODULE VALIDATOR
#======================
#!/usr/intel/bin/perl -dw

use vars qw( $TOP_MODULE $DEBUG );

use pm::Common;

use package_name::module;

$DEBUG=0;
$TOP_MODULE="Module Validator";

&error(-1, "Inappropriate arguments specified! One, and only one, modu
+le must be defined") if($#ARGV != 0);

&error(-2, "Bad module syntax. Only a-z, A-Z, 0-9, '_'  are allowed fo
+r the name, with :: as package scoping separators") if($ARGV[0] =~ /[
+^\w:\.]/);

local $@=0;

eval 'require "'.$ARGV[0].'";';

if($@) {
    &error(1, "Failed include stage for '$ARGV[0]'. Error message:\n$@
+");
} else {

# ...

}

print "$ARGV[0]: Valid\n";

sub error { &Common::error(@_); }

#======================
#END MODULE VALIDATOR
#======================

[download]
try/foo.pm: 
#=====================
#BEGIN FOO::TRY
#=====================
package foo::try;
                                                                      
+                                                                     
+                                                        
use pm::Common;                                                       
+                                                                     
+                                                                     
+   

1;
#=====================
#END FOO::TRY
#=====================

[download]
Run / output: 
filc8166[559]% perl -I`pwd` ./bin/Module_Validator.pl foo::try
                                                                      
+                                                                     
+                                                          
Loading DB routines from perl5db.pl version 1.27
Editor support available.
                                                                      
+                                                                     
+                                                          
Enter h or `h h' for help, or `man perldebug' for more help.
                                                                      
+                                                                     
+                                                          
  DB<1> s
main::((eval 7)[./bin/Module_Validator.pl:16]:1):
1:      require "foo::try";
main::(./bin/Module_Validator.pl:7):
7:
  DB<2> c
(Module Validator) ERROR: Failed include stage for 'foo::try'. Error m
+essage:
Can't locate foo::try in @INC (@INC contains: /nfs/fm/disks/fm_vt_n190
+29/users/gwcooper/vibe_regress /usr/intel/pkgs/perl/5.8.5/lib/5.8.5/i
+686-linux-64int /usr/intel/pkgs/perl/5.8.5/lib/5.8.5 /usr/intel/pkgs/
+perl/5.8.5/lib/site_perl/5.8.5/i686-linux-64int /usr/intel/pkgs/perl/
+5.8.5/lib/site_perl/5.8.5 /usr/intel/pkgs/perl/5.8.5/lib/site_perl .)
+ at (eval 7)[./bin/Module_Validator.pl:16] line 1.
                                                                      
+                                                                     
+                                                          
Backtrace:  at ./bin/Module_Validator.pl line 40
        main::error(1, 'Failed include stage for \'foo::try\'. Error m
+essage:\x{a}Can\'t ...') called at ./bin/Module_Validator.pl line 19
Debugged program terminated.  Use q to quit or R to restart,
  use O inhibit_exit to avoid stopping after program termination,
  h q, h R or h O to get additional info.
  DB<2> q
filc8166[560]% pwd
/nfs/fm/disks/fm_vt_n19029/users/gwcooper/vibe_regress
filc8166[561]% ls foo/
try.pm

[download]

Any ideas what could be wrong?

Thanks in advance!

-Garrett

Replies are listed 'Best First'.
Re: Issues with including via eval 'require'
by jettero (Monsignor) on Apr 26, 2007 at 17:31 UTC

    I think you probably don't want the extra quotes. require "filename" means to require a filename, where require File::Name means to search @INC for a class (filename of File/Name.pm).

    The usual reason behind the use of eval "require ..." is to make the contents of your variable into a bare word. The other reason, obviously, is to trap errors if the module is missing; or to execute the require at runtime instead of doing it before main execution.

    You might also consider interpolation, so you don't have to explicitly concatenate like that. 

    eval "require $ARGV[0]"; die $@ if $@;

    [download]

    I have assumed that "foo::try" actually is in another file. If it's in the same file, your require is never going to work. :)

    -Paul

[reply]
[d/l]
[select]
      Ah, brilliant! That did the trick! Sometimes I get confused between "require ''" and "require", I think.. Thank you! PS foo::try was in another file :).
[reply]
      require always happens at runtime.
[reply]

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