NAME

File::Package - test load a program module with a package of the same name

SYNOPSIS

 ##########
 # Subroutine interface
 #
 use File::Package qw(is_package_loaded load_package);

 $yes = is_package_loaded($package, $program_module);

 $error   = load_package($program_module);
 $error   = load_package($program_module, @import);
 $error   = load_package($program_module, [@package_list]);
 $error   = load_package($program_module, @import, [@package_list]);

 ##########
 # Class Interface
 # 
 use File::Package;

 $yes = is_package_loaded($package, $program_module);

 $error   = File::Package->load_package($program_module);
 $error   = File::Package->load_package($program_module, @import);
 $error   = File::Package->load_package($program_module, [@package_list]);
 $error   = File::Package->load_package($program_module, @import, [@package_list]);

DESCRIPTION

Although a program module and package have the same name syntax, they are entirely different. A program module is a file. A package is a hash of symbols, a symbol table. The Perl convention is that the names for each are the same which enhances the appearance that they are the same when in fact they are different.

is_package_loaded subroutine

 $package = is_package_loaded($program_module, $package)

The is_package_loaded subroutine determines if the $package is present and the $progarm_module loaded. If $package is absent, 0 or '', $package is set to the program_module.

load_package subroutine

  $error = load_package($program_module, @import, [@package_list]);

The load_package subroutine attempts to capture any load problems by loading the package with a "require " under an eval and capturing all the "warn" and $@ messages.

If the $program_module load is successful, the checks that the packages in the @package list are present. If @package list is absent, the $program_module uses the program_module name as a list of one package.

Finanly the $program_module subroutine will import the symbols in the @import list. If @import is absent $program_module subroutine does not import any symbols; if @import is '', all symbols are imported. A @import of 0 usually results in an $error.

The $program_module traps all load errors and all import Carp::Crock errors and returns them in the $error string.

One very useful application of the load_package subroutine is in test scripts. If a package does load, it is very helpful that the program does not die and reports the reason the package did not load. This information is readily available when loaded at a local site. However, it the load occurs at a remote site and the load crashes Perl, the remote tester usually will not have this information readily available.

Other applications include using backup alternative software if a package does not load. For example if the package 'Compress::Zlib' did not load, an attempt may be made to use the gzip system command.

BUGS

The load_package cannot load program modules whose name contain the '-' characters. The 'eval' function used to trap the die errors believes it means subtraction.

REQUIREMENTS

Coming soon.

DEMONSTRATION

 ~~~~~~ Demonstration overview ~~~~~

Perl code begins with the prompt

 =>

The selected results from executing the Perl Code follow on the next lines. For example,

 => 2 + 2
 4

 ~~~~~~ The demonstration follows ~~~~~

 =>     use File::Package;
 =>     my $uut = 'File::Package';
 => my $error = $uut->load_package( 'File::Basename' )
 ''

 => $error = $uut->load_package( '_File_::BadLoad' )
 'Cannot load _File_::BadLoad
        syntax error at E:/User/SoftwareDiamonds/installation/t/File/_File_/BadLoad.pm line 13, near "$FILE "
        Global symbol "$FILE" requires explicit package name at E:/User/SoftwareDiamonds/installation/t/File/_File_/BadLoad.pm line 13.
        Compilation failed in require at (eval 4) line 1.
        Scalar found where operator expected at E:/User/SoftwareDiamonds/installation/t/File/_File_/BadLoad.pm line 13, near "$FILE"
                (Missing semicolon on previous line?)
        '

 => $uut->load_package( '_File_::BadPackage' )
 '# _File_::BadPackage file but package(s) _File_::BadPackage absent.
 '

 => $uut->load_package( '_File_::Multi' )
 '# _File_::Multi file but package(s) _File_::Multi absent.
 '

 => $error = $uut->load_package( '_File_::Hyphen-Test' )
 'Cannot load _File_::Hyphen-Test
        syntax error at (eval 7) line 1, near "require _File_::Hyphen-"
        Warning: Use of "require" without parens is ambiguous at (eval 7) line 1.
        '

 => !defined($main::{'find'})
 '1'

 => $error = $uut->load_package( 'File::Find', 'find', ['File::Find'] )
 ''

 => defined($main::{'find'})
 '1'

 => !defined($main::{'finddepth'})
 '1'

 => $uut->load_package( 'File::Find', 'Jolly_Green_Giant')
 '"Jolly_Green_Giant" is not exported by the File::Find module
 Can't continue after import errors'

 => !defined($main::{'finddepth'})
 '1'

 => $error = $uut->load_package( 'File::Find', '')
 ''

 => defined($main::{'finddepth'})
 '1'

QUALITY ASSURANCE

Running the test script 'Package.t' found in the "File-Package-$VERSION.tar.gz" distribution file verifies the requirements for this module.

All testing software and documentation stems from the Software Test Description (STD) program module 't::File::Package', found in the distribution file "File-Package-$VERSION.tar.gz".

The 't::File::Package' STD POD contains a tracebility matix between the requirements established above for this module, and the test steps identified by a 'ok' number from running the 'Package.t' test script.

The t::File::Package' STD program module '__DATA__' section contains the data to perform the following:

• to generate the test script 'Package.t'

• generate the tailored STD POD in the 't::File::Package' module,

• generate the 'Package.d' demo script,

• replace the POD demonstration section herein with the demo script 'Package.d' output, and

• run the test script using Test::Harness with or without the verbose option,

To perform all the above, prepare and run the automation software as follows:

• Install "Test_STDmaker-$VERSION.tar.gz" from one of the respositories only if it has not been installed:

  • http://www.softwarediamonds/packages/

  • http://www.perl.com/CPAN-local/authors/id/S/SO/SOFTDIA/

• manually place the script tmake.pl in "Test_STDmaker-$VERSION.tar.gz' in the site operating system executable path only if it is not in the executable path

• place the 't::File::Package' at the same level in the directory struture as the directory holding the 'File::Package' module

• execute the following in any directory:

   tmake -test_verbose -replace -run -pm=t::File::Package

NOTES

FILES

The installation of the "File-Package-$VERSION.tar.gz" distribution file installs the 'Docs::Site_SVD::File_Package' SVD program module.

The __DATA__ data section of the 'Docs::Site_SVD::File_Package' contains all the necessary data to generate the POD section of 'Docs::Site_SVD::File_Package' and the "File-Package-$VERSION.tar.gz" distribution file.

To make use of the 'Docs::Site_SVD::File_Package' SVD program module, perform the following:

• install "ExtUtils-SVDmaker-$VERSION.tar.gz" from one of the respositories only if it has not been installed:

  • http://www.softwarediamonds/packages/

  • http://www.perl.com/CPAN-local/authors/id/S/SO/SOFTDIA/

• manually place the script vmake.pl in "ExtUtils-SVDmaker-$VERSION.tar.gz' in the site operating system executable path only if it is not in the executable path

• Make any appropriate changes to the __DATA__ section of the 'Docs::Site_SVD::File_Package' module. For example, any changes to 'File::Package' will impact the at least 'Changes' field.

• Execute the following:

   vmake readme_html all -pm=Docs::Site_SVD::File_Package

AUTHOR

The holder of the copyright and maintainer is

<support@SoftwareDiamonds.com>

COPYRIGHT NOTICE

Copyrighted (c) 2002 Software Diamonds

All Rights Reserved

BINDING REQUIREMENTS NOTICE

Binding requirements are indexed with the pharse 'shall[dd]' where dd is an unique number for each header section. This conforms to standard federal government practices, 490A ("3.2.3.6" in STD490A). In accordance with the License, Software Diamonds is not liable for any requirement, binding or otherwise.

LICENSE

Software Diamonds permits the redistribution and use in source and binary forms, with or without modification, provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

SOFTWARE DIAMONDS, http::www.softwarediamonds.com, PROVIDES THIS SOFTWARE 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SOFTWARE DIAMONDS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING USE OF THIS SOFTWARE, EVEN IF ADVISED OF NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE POSSIBILITY OF SUCH DAMAGE.

cpanm File::Package

perl -MCPAN -e shell
install File::Package