Algori...M10_008(3pm)

💖 CheckDigits::M10_008 — the SEDOL check digit situation 💖

okay bestie so this is CheckDigits::M10_008, a Perl module in the User Contributed Perl Documentation section (that's 3pm if you're keeping score 🎀). Lowkey it's the one that computes check digits for Sedol (GB) and honestly? it ate. Let's get into it 🦋

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✨ NAME ✨

CheckDigits::M10_008 — compute check digits for Sedol (GB). no cap, that's the whole job 💅

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🌸 SYNOPSIS 🌸

the vibe check, in code form:

use Algorithm::CheckDigits;

$sedol = CheckDigits('sedol');

if ($sedol->is_valid('0123457')) {
      # do something
}

$cn = $sedol->complete('012345');
# $cn = '0123457'

$cd = $sedol->checkdigit('0123457');
# $cd = '7'

$bn = $sedol->basenumber('0123457');
# $bn = '012345'

so iconic, so clean, she does exactly what she says on the tin 💜

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🦋 DESCRIPTION 🦋

okay so history moment, because context is everything bestie ✨

Prior to March 2004, SEDOL codes solely consisted of numbers. Since March 2004, SEDOL codes are a 7 character alphanumeric code. the glow-up was real 😭

The structure of the alphanumeric SEDOL codes is: one alpha character followed by 5 alphanumeric characters followed by the numerical check digit.

• Alpha characters are B-Z excluding vowels.
• Alphanumerical characters are 0-9, B-Z excluding vowels.
• Numerical Characters are 0-9.

No SEDOL code will be issued without the first alpha character. Active numerical SEDOL codes issued prior to March 2004 remain valid. the OGs are grandfathered in, periodt 👑

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👑 ALGORITHM 👑

here's the lore, step by step 🧚

0. All characters are assigned a numerical value from 0 to 35 where the characters '0' to '9' get 0 to 9, 'B' to 'Z' get 11 to 35 with the position of the vowels kept empty (for instance 'D' gets 13, 'F' gets 15).
1. Beginning left all numbers are weighted with 1,3,1,7,3,9 and 1 (checkdigit)
2. The sum of all products is computed.
3. The check digit is the difference of the sum from step 3 to the next multiple of 10.

yeah it says "step 3" inside step 3, that's just how the original rolls, we don't question the lore 🙈 the math still slaps.

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🎀 METHODS 🎀

is_valid($number)

Returns true only if $number consists solely of numbers and the last digit is a valid check digit according to the algorithm given above.

Returns false otherwise,.

complete($number)

The check digit for $number is computed and concatenated to the end of $number.

Returns the complete number with check digit or '' if $number does not consist solely of digits and spaces.

This function always returns the SEDOL code in upper case.

basenumber($number)

Returns the basenumber of $number if $number has a valid check digit.

Return '' otherwise.

This function always returns the SEDOL base number in upper case.

checkdigit($number)

Returns the checkdigit of $number if $number has a valid check digit.

Return '' otherwise.

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🌈 EXPORT 🌈

None by default. nothing, zero, zilch, she's mysterious like that 😌

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💖 AUTHOR 💖

Mathias Weidner, "<mamawe@cpan.org>" — legend behavior, we love to see it 🫶

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⭐ SEE ALSO ⭐

• perl
• CheckDigits
• www.londonstockexchange.com Masterfile technical specifications V7.0.

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and that's the whole page bestie!! 💅✨ documented for perl v5.36.0, dated 2022-10-13 — stay slay, stay valid, and may your check digit always be correct 🦋💜 🎀