Seeking obscure out-of-print O'Reilly Perl code example
November 17, 2018 7:32 PM   Subscribe

I recall coming across a Perl coding example perhaps 15-25 years ago in one of the O'Reilly Perl books, and 'm hoping a graybeard or book collector can help.

I've been buying/perusing O'Reilly books since they were plastic-spiral bound, and I spent a fair amount of time in that section of Computer Literacy and Stacey's Cupertino back when they existed.

The coding example involved reproducing the OpenVMS 'DIFFERENCE' command. Cant't find it in Google etc., Scribd, O'Reilly's website or on Safari Books Online. I suspect the example predates O'Reilly's PDF publishing era and was deleted for subsequent editions of whatever book in which it was published.

I can easily write such a beast myself these days, but I would like to know which book/edition it was in so I may confirm my memory.

I am bracing myself for 0 replies to this amazingly arcane and obscure question.
posted by zaixfeep to Computers & Internet (14 answers total) 1 user marked this as a favorite
I’m pretty sure that it’s not in the first edition Camel book. (My copy is at work, so I can’t check it now, but I have it damn near memorized.)
posted by monotreme at 7:40 PM on November 17, 2018

Response by poster: Thanks. You remind me I was unclear -- by 'Perl books' I also include tangents like Perl for System Administration etc.
posted by zaixfeep at 7:45 PM on November 17, 2018 [1 favorite]

I haven't found your answer, but I will note the VMS command is "DIFFERENCES", not "DIFFERENCE".
posted by fings at 8:01 PM on November 17, 2018 [1 favorite]

Then again, VMS DCL would only pay attention to the first 4 characters of a command, as I recall, so you could just type "DIFF" and it would work.
posted by fings at 8:15 PM on November 17, 2018

It's not in 1998's Mastering Algorithms with Perl (just Baeza-Yates-Gonnet and Wu-Manber string differences). However, by that time Algorithm::Diff was already a thing. Originally it seems to have been by mjd Diff - Compare two files and print differences. You might want to ask mjd if his early Diff was in an early O'Reilly book.

Assuming VMS DIFFERENCES is the same as UNIX-y diff.
posted by zengargoyle at 9:30 PM on November 17, 2018 [1 favorite]

If it helps, it does not appear to be in the first edition (2000) of Perl for System Administration. As a side note, if that book would be at all useful to you, drop me a MeMail and I'll sent it to you. Tonight's probably the first time in at least 10 years since it's been opened.
posted by Candleman at 9:49 PM on November 17, 2018

Also FWIW, skimming the indexes of Learning Perl second edition (1997) and Programming Perl second edition (1996) did not have anything that looks like what you're looking for.
posted by Candleman at 10:01 PM on November 17, 2018

I checked Computer Science & Perl Programming, which is an O'Reilly-published collection of Perl Journal articles, and don't see any sign of it, including no entries for "DIFFERENCES" or OpenVMS in the index.
posted by zachlipton at 10:03 PM on November 17, 2018 [1 favorite]

It's not in The Perl Cookbook.
posted by Obscure Reference at 5:01 AM on November 18, 2018

I still have the Perl CD Bookshelf Version 2.0 (containing Perl in a Nutshell, Programming Perl 3rd Edition, Advanced Perl Programming, Perl Cookbook, and Perl for System Administration) accessible on a server. There are only two VMS references in the master index and neither of them is what you're looking for. I didn't see anything promising under "diff" or "comparing" either.
posted by fedward at 5:33 AM on November 18, 2018 [1 favorite]

I've heard that Text::Diff and Algorithm::Diff aren't the most solid references for this.
posted by Pronoiac at 10:14 AM on November 18, 2018

I guess I'm asking, are you interested in the algorithms, in being able to adjust it? I hit a pathological edge case with GNU diff and I've considered redoing it for fun and as an excuse to try out a new language; I've gathered some papers and code. Would you be interested in links?
posted by Pronoiac at 10:26 AM on November 18, 2018

Response by poster: * Yes, it's DIFFERENCES, I typo'd
* I currently use 'diff -y -W width -w -b -B' to cargo-cult simulate DIFF now. Option -y wasn't available when what I am looking for was published
* I want to confirm my memory and revisit how the author approached the problem. At the time I saw it, I was an ultra-hardcore VMS SYS$GEEK() but illiterate in Perl, so I couldn't appreciate the author's work. I am now over 15+ years from my last VMS use and well-grounded in Perl, so I wanted to revisit the article with my current knowledge
* Upon further recollection, it might it have been in an old version of one of O'Reilly's Cookbooks or Power Tools books
Cats, consider yourself herded :-) End threadsit
posted by zaixfeep at 3:00 PM on November 18, 2018

Response by poster: I'm marking this resolved because no further answers are likely forthcoming. I may email O'Reilly directly, though I doubt their institutional memory goes back that far anymore - even Tim O'R himself stepped away from day-to-day mgmt there years ago.
posted by zaixfeep at 1:19 PM on December 26, 2018

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