altmetric / identifiers Goto Github PK

For an ISBN [1], can the extractor return a value that retains the hyphens?

Given the variable length of ISBN parts, it's not possible to reconstruct the hyphens or spaces once they are removed. It's desirable to validate and extract an ISBN while retaining the spaces or hyphens in it.

Identifiers::ISBN.extract '978-92-95055-02-5'
=> ["9789295055025"]

• [1] https://www.isbn-international.org/content/what-isbn

The WorldBank has a DOI which ends in a dot.

https://doi.org/10.1596/1020-797X-10_2_7.

Unfortunately, DOI.extract doesn't appear to support that.

[1] pry(main)> Identifiers::DOI.extract('https://doi.org/10.1596/1020-797X-10_2_7.')
=> ["10.1596/1020-797x-10_2_7"]

The current regular expression identifies the character used as hyphen and then allow for it to be repeated within the string:

https://github.com/altmetric/identifiers/blob/master/lib/identifiers/isbn.rb#L7-L10

( \p{Pd} matches any kind of hyphen or dash and \2? matches the same text as most recently matched by the 2nd capturing group)

However in some rare instances we found ISBNs containing different special characters used as hyphen within the same ISBN, e.g. 978–3−200–01908–9:

e.g.
-: 002D - UTF-8: 2D (hyphen / minus)
–: 2013 - UTF-8: E2 80 93 (en dash)
−: 2212 - UTF-8: E2 88 92 (minus sign; note: this is not recognised by \p{Pd})

The current behaviour is the result of an improvement introduced last year (2e8a138)

Currently, gem extracts multiple isbns from a string of digits separated by '-'.
Here is the example:

pry(main)> Identifiers::ISBN.extract('0-1884-0-3140-0-4396-0-5652-0-4396-0-2826').uniq
=> ["9780188403145", "9780439605656"]

This should not be happening as valid isbns should be separate entities.

I tried to use the library like so:

Isbn::extract("9780854045877 9781847552518")

and got [] back.

If I use it on

Isbn::extract("9780854045877\n9781847552518")

though it gives me both ISBNs.
Is there a reason why it doesn't extract anything in the first scenario?

Always extract using same separators ( , - or none). Fix:

Identifiers::ISBN.extract("978-3-319-18019-9 978-3-319-18020-5")
=> ["9783319180199", "9783319180205", "9781801999786"]