Module Version: 0.04

# NAME

Business::PT::NIF - Validate Portuguese NIF (Número Fiscal de Contribuinte)

Version 0.01

# SYNOPSIS

```    use Business::PT::NIF;

if ( valid_nif(\$nif) ) {
# ...
}```

# FUNCTIONS

## valid_nif

Validates Portuguese NIF's.

Returns a true value if the validation succeeds, a false one otherwise.

Currently, validation is done only by the control digit, as follows:

``` 1) NIF is matched with /^\d{9}\$/ (nine consecutive digits with nothing more)
2) Control digit (last one, the ninth) is removed and store
3) First digit is multiplied by 9, second by 8, third by 7, fourth by 6, fifth
by 5, sixth by 4, seventh by 3, eighth by 2
4) All the results of the multiplication are summed
5) Modulo of the sum by 11 is found
6) Complement of the sum by 11 is found
7) Control digit is compared to said complement```

Example for NIF 136695973:

``` 1) NIF is matched agains /^\d{9}\$/, test passes
2) Control digit is 3 (last digit)
3) Multiplication: 1*9, 3*8, 6*7, 6*6, 9*5, 5*4, 9*3, 7*2
4) Sum: 217
5) 217 % 11 = 8
6) 11 - 8 = 3
7) 3 == 3, test passes```

When the complement (the result of step 6) is greater than 9, the number is assumed to be 0.

# AUTHOR

Jose Castro, `<cog at cpan.org>`

# BUGS

Please report any bugs or feature requests to `bug-business-pt-nif at rt.cpan.org`, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Business-PT-NIF. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

# SUPPORT

You can find documentation for this module with the perldoc command.

`    perldoc Business::PT::NIF`

You can also look for information at: