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.\"
.IX Title "Business::ISMN 3"
.TH Business::ISMN 3 2024-02-17 "perl v5.38.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
Business::ISMN \- work with International Standard Music Numbers
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\&        use Business::ISMN;
\&
\&        $ismn_object = Business::ISMN\->new(\*(AqM021765430\*(Aq);
\&        $ismn_object = Business::ISMN\->new(\*(AqM\-021\-76543\-0\*(Aq);
\&
\&        #print the ISMN with hyphens at positions specified
\&        #by constructor
\&        print $ismn_object\->as_string;
\&
\&        #print the ISMN with hyphens at specified positions.
\&        #this not does affect the default positions
\&        print $ismn_object\->as_string([]);
\&
\&        #print the publication country or publisher code
\&        print $ismn\->country;         # two letter country string
\&        print $ismn\->publisher_code;  # digits
\&
\&        #check to see if the ISMN is valid
\&        $ismn_object\->is_valid;
\&
\&        #fix the ISMN checksum.  BEWARE:  the error might not be
\&        #in the checksum!
\&        $ismn_object\->fix_checksum;
\&
\&        # create an EAN13 barcode in PNG format
\&        $ismn_object\->png_barcode;
\&
\&        #EXPORTABLE FUNCTIONS
\&
\&        use Business::ISMN qw( is_valid_checksum
\&                ismn_to_ean ean_to_ismn );
\&
\&        #verify the checksum
\&        if( is_valid_checksum(\*(Aq0123456789\*(Aq)
\&                eq Business::ISMN::GOOD_ISMN )
\&                { ... }
\&
\&        #convert to EAN (European Article Number)
\&        $ean = ismn_to_ean(\*(Aq1565921496\*(Aq);
\&
\&        #convert from EAN (European Article Number)
\&        $ismn = ean_to_ismn(\*(Aq9781565921498\*(Aq);
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
.SS Methods
.IX Subsection "Methods"
.IP new($ismn) 4
.IX Item "new($ismn)"
The constructor accepts a scalar representing the ISMN.
.Sp
The string representing the ISMN may contain characters
other than \f(CW\*(C`[0\-9mM]\*(C'\fR, although these will be removed in the
internal representation.  The resulting string must look
like an ISMN \- the first character is an 'M' and the
following nine characters must be digits.
.Sp
The constructor attempts to determine the country
code and the publisher code.  If these data cannot
be determined, the constructor sets \f(CW\*(C`$obj\->is_valid\*(C'\fR
to something other than \f(CW\*(C`GOOD_ISMN\*(C'\fR.
An object is still returned and it is up to the program
to check \f(CW\*(C`$obj\->is_valid\*(C'\fR for one of five values (which
may be exported on demand). The actual values of these
symbolic versions are the same as those from previous
versions of this module which used literal values.
.Sp
.Vb 4
\&        Business::ISMN::INVALID_PUBLISHER_CODE
\&        Business::ISMN::BAD_CHECKSUM
\&        Business::ISMN::GOOD_ISMN
\&        Business::ISMN::BAD_ISMN
.Ve
.Sp
The string passed as the ISMN need not be a valid ISMN as
long as it superficially looks like one.  This allows one to
use the \f(CWfix_checksum()\fR method.  Despite the disclaimer in
the discussion of that method, the author has found it
extremely useful.  One should check the validity of the ISMN
with \f(CWis_valid()\fR rather than relying on the return value
of the constructor.  If all one wants to do is check the
validity of an ISMN, one can skip the object-oriented
interface and use the \f(CWis_valid_checksum()\fR function
which is exportable on demand.
.Sp
If the constructor decides it cannot create an object, it
returns \f(CW\*(C`undef\*(C'\fR.  It may do this if the string passed as the
ISMN cannot be munged to the internal format meaning that it
does not even come close to looking like an ISMN.
.IP ismn 4
.IX Item "ismn"
Returns the ISMN as a string
.IP country 4
.IX Item "country"
.PD 0
.IP publisher 4
.IX Item "publisher"
.PD
Returns the country associated with the publisher code. This method was
formerly called \f(CW\*(C`publisher\*(C'\fR (and that still works), but it's really
returns a two letter country code.
.IP publisher_code 4
.IX Item "publisher_code"
Returns the publisher code or \f(CW\*(C`undef\*(C'\fR if no publisher code was found.
.IP article_code 4
.IX Item "article_code"
Returns the article code or \f(CW\*(C`undef\*(C'\fR if no article
code was found.
.IP checksum 4
.IX Item "checksum"
Returns the checksum or \f(CW\*(C`undef\*(C'\fR if no publisher
code was found.
.IP hyphen_positions 4
.IX Item "hyphen_positions"
Returns the list of hyphen positions as determined from the
country and publisher codes.  the \f(CW\*(C`as_string\*(C'\fR method provides
a way to temporarily override these positions and to even
forego them altogether.
.IP "\fBas_string()\fR,  as_string([])" 4
.IX Item "as_string(), as_string([])"
Return the ISMN as a string.  This function takes an
optional anonymous array (or array reference) that specifies
the placement of hyphens in the string.  An empty anonymous array
produces a string with no hyphens. An empty argument list
automatically hyphenates the ISMN based on the discovered
publisher code.  An ISMN that is not valid may
produce strange results.
.Sp
The positions specified in the passed anonymous array
are only used for one method use and do not replace
the values specified by the constructor. The method
assumes that you know what you are doing and will attempt
to use the least three positions specified.  If you pass
an anonymous array of several positions, the list will
be sorted and the lowest three positions will be used.
Positions less than 1 and greater than 9 are silently
ignored.
.IP is_valid 4
.IX Item "is_valid"
Returns \f(CW\*(C`Business::ISMN::GOOD_ISMN\*(C'\fR if the checksum is valid and the
country and publisher codes are defined.
.Sp
Returns \f(CW\*(C`Business::ISMN::BAD_CHECKSUM\*(C'\fR if the ISMN does not pass
the checksum test. The constructor accepts invalid ISMN's so that
they might be fixed with \f(CW\*(C`fix_checksum\*(C'\fR.
.Sp
Returns \f(CW\*(C`Business::ISMN::INVALID_PUBLISHER_CODE\*(C'\fR if a publisher code
could not be determined.
.Sp
Returns \f(CW\*(C`Business::ISMN::BAD_ISMN\*(C'\fR if the string has no hope of ever
looking like a valid ISMN.  This might include strings such as \f(CW"abc"\fR,
\&\f(CW"123456"\fR, and so on.
.IP is_valid_country_code 4
.IX Item "is_valid_country_code"
.PD 0
.IP is_valid_publisher_code 4
.IX Item "is_valid_publisher_code"
.PD
Returns true if the country code is valid, and false otherwise.
.Sp
This method was formerly called \f(CW\*(C`is_valid_publisher_code\*(C'\fR. That's
deprecated but still there.
.IP \fBfix_checksum()\fR 4
.IX Item "fix_checksum()"
Replace the tenth character with the checksum the
corresponds to the previous nine digits.  This does not
guarantee that the ISMN corresponds to the product one
thinks it does, or that the ISMN corresponds to any product
at all.  It only produces a string that passes the checksum
routine.  If the ISMN passed to the constructor was invalid,
the error might have been in any of the other nine positions.
.ie n .IP $obj\->\fBas_ean()\fR 4
.el .IP \f(CW$obj\fR\->\fBas_ean()\fR 4
.IX Item "$obj->as_ean()"
Converts the ISMN to the equivalent EAN (European Article Number).
No pricing extension is added.  Returns the EAN as a string.  This
method can also be used as an exportable function since it checks
its argument list to determine what to do.
.IP \fBpng_barcode()\fR 4
.IX Item "png_barcode()"
Creates a PNG image of the EAN13 barcode which corresponds to the
ISMN. Returns the image as a string.
.SS "EXPORTABLE FUNCTIONS"
.IX Subsection "EXPORTABLE FUNCTIONS"
Some functions can be used without the object interface.  These
do not use object technology behind the scenes.
.IP is_valid_checksum('M021765430') 4
.IX Item "is_valid_checksum('M021765430')"
Takes the ISMN string and runs it through the checksum
comparison routine.  Returns \f(CW\*(C`Business::ISMN::GOOD_ISMN\*(C'\fR
if the ISMN is valid, \f(CW\*(C`Business::ISMN::BAD_CHECKSUM\*(C'\fR if the
string looks like an ISMN but has an invalid checksum, and
\&\f(CW\*(C`Business::ISMN::BAD_ISMN\*(C'\fR if the string does not look like
an ISMN.
.IP ismn_to_ean('M021765430') 4
.IX Item "ismn_to_ean('M021765430')"
Takes the ISMN string and converts it to the equivalent
EAN string.  This function checks for a valid ISMN and will return
undef for invalid ISMNs, otherwise it returns the EAN as a string.
Uses as_ean internally, which checks its arguments to determine
what to do.
.IP ean_to_ismn('9790021765439') 4
.IX Item "ean_to_ismn('9790021765439')"
Takes the EAN string and converts it to the equivalent
ISMN string.  This function checks for a valid ISMN and will return
undef for invalid ISMNs, otherwise it returns the EAN as a string.
Uses as_ean internally, which checks its arguments to determine
what to do.
.SH "TO DO"
.IX Header "TO DO"
.IP \(bu 4
I need more ISMN numbers for tests
.SH "SOURCE AVAILABILITY"
.IX Header "SOURCE AVAILABILITY"
This source is in Github:
.PP
.Vb 1
\&    https://github.com/briandfoy/business\-ismn/
.Ve
.SH AUTHOR
.IX Header "AUTHOR"
brian d foy, \f(CW\*(C`<briandfoy@pobox.com>\*(C'\fR
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
Copyright © 2001\-2024, brian d foy <briandfoy@pobox.com>. All rights reserved.
.PP
You may redistribute this under the terms of the Artistic License 2.0.