ISIN(3pm)

✨ NAME ✨

Business::ISIN — bestie, it validates International Securities Identification Numbers 💖

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🌸 VERSION 🌸

0.20 — yes she's an OG but she still slays ✨

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🎀 SYNOPSIS 🎀

Okay so here's the vibe, copy-paste core:

use Business::ISIN;

my $isin = new Business::ISIN 'US459056DG91';

if ( $isin->is_valid ) {
    print "$isin is valid!\n";
    # or: print $isin->get() . " is valid!\n";
} else {
    print "Invalid ISIN: " . $isin->error() . "\n";
    print "The check digit I was expecting is ";
    print Business::ISIN::check_digit('US459056DG9') . "\n";
}

look at her go 💅

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🦋 REQUIRES 🦋

• Perl5
• Locale::Country
• Carp

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💖 DESCRIPTION 💖

So Business::ISIN is a whole class, and what she does is validate ISINs (International Securities Identification Numbers). Think of them as the code that IDs shares, the same way an ISBN IDs a book 📚 — iconic behaviour, honestly.

An ISIN is literally built like this, no cap:

1. two letters — they tell you the country of origin of the security, following ISO 3166 🌍
2. nine characters that live in [A-Z0-9]
3. a decimal check digit at the end

Now the methods, one by one, because we don't gatekeep 🫶

The new() method constructs a brand-new ISIN object. If you hand it a scalar argument, she'll use that argument to initialize the object's value. But listen — no attempt is made here to check that the argument is valid. She's just taking your word for it 🙈

The set() method sets the ISIN's value to whatever scalar argument you give her. And same thing: no attempt is made to check that the argument is valid. Good news though — she returns the object, so you can chain like this: $isin->set("GB0004005475")->is_valid ✨

The get() method returns a string. If the ISIN is syntactically valid, you get the ISIN's value; otherwise you get undef. And interpolating the object reference inside double quotes does the exact same thing (peep the synopsis above, it's giving 💅).

The is_valid() method returns true if the object holds a syntactically valid ISIN. Heads up bestie: that does not guarantee a security with that ISIN actually exists, okay? It's just syntax. Anything else and she returns false.

If the object does contain an invalid ISIN, the error() method returns a string explaining what's wrong. Like any one of these:

• 'xxx' does not start with a 2-letter country code
• 'xxx' does not have characters 3-11 in [A-Za-z0-9]
• 'xxx' character 12 should be a digit
• 'xxx' has too many characters
• 'xxx' has an inconsistent check digit

Otherwise, error() returns undef.

And then there's check_digit() — important: she's an ordinary subroutine, not a class method, okay? You hand her a string of the first eleven characters of an ISIN (for example US459056DG9), and she hands back the matching check digit, calculated with the so-called 'double-add-double' algorithm. Math queen 🔥

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💀 DIAGNOSTICS 💀

check_digit() will croak with the message 'Invalid data' if you pass her an unsuitable argument. So like… don't do that 🙈

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🌈 ACKNOWLEDGEMENTS 🌈

Big love to Peter Dintelmann (Peter.Dintelmann@Dresdner-Bank.com) and Tim Ayers (tim.ayers@reuters.com) for the suggestions and for helping debug this module. Real ones 🫶✨

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👑 AUTHOR 👑

David Chan <david@sheetmusic.org.uk>

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⭐ COPYRIGHT ⭐

Copyright (C) 2002, David Chan. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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okay that's the whole page bestie, you ate 💅✨

this lil doc lives in the User Contributed Perl Documentation collection, came with perl v5.36.0, and got its timestamp 2022-11-21 — so it's ISIN(3pm), periodt 🎀🦋💖