## SYNOPSIS

use Business::BR::Ids::Common qw(_dot _canon_i _canon_id);

my @digits = (1, 2, 3, 3);

my @weights = (2, 5, 2, 6);

my $dot = _dot(\@weights, \@digits); # computes 2*1+5*2+2*3+6*3 = 36

# computes the sum of digits of ( 2*1, 5*2, 2*3, 6*3 )

# which is 2 + (1 + 0) + 6 + (1 + 8) = 18

my $s = _dot_10(\@weights, \@digits);

_canon_i(342222, size => 7); # returns '0342222'

_canon_i('12.28.8', size => 5); # returns '12288'

_canon_i(342222, size => 7); # returns '0342222'

_canon_i('12.28.8', size => 5); # returns '12288'

_canon_id('A12.3-B', size => 5); # returns 'A123B'

## DESCRIPTION

This module is meant to be private for Business-BR-Ids distributions. It is a common placeholder for code which is shared among other modules of the distribution.Actually, the only code here is the computation of the scalar product between two array refs. In the future, this module can disappear being more aptly named and even leave the Business::BR namespace.

**_dot**-
$s = _dot(\@a, \@b);

Computes the scalar (or dot) product of two array refs:

sum( a[i]*b[i], i = 0..$#a )

Note that due to this definition, the second argument should be at least as long as the first argument.

**_dot_10**-
$s = _dot_10(\@a, \@b);

Computes the product of corresponding elements in the array refs and then takes the sum of its digits. (Used for computing IE/MG.)

**_canon_i**-
$qs = _canon_i($s, size => 8)

If the argument is a number, formats it to the specified size. Then, strips any non-digit character. If the argument is a string, it just strips non-digit characters.

**_canon_id**-
$qs = _canon_id($s, size => 8)

If the argument is a number, formats it to the specified size. Then, strips any non-digit character. If the argument is a string, it just strips characters matching

`"/[\W_]/"`.

## EXPORT

None by default.
You can explicitly ask for `"_dot()"` which
is a sub to compute the dot product between two array refs
(used for computing check digits). There are also
`"_dot_10"`, `"_canon_i"` and `"_canon_id"` to be exported on demand.

## AUTHOR

A. R. Ferreira, <[email protected]>## COPYRIGHT AND LICENSE

Copyright (C) 2005-2007 by A. R. FerreiraThis library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.