(that) you haven't read the good Perl books
If every good Perl book mentioned in it "it's Perl, not PERL", then I'd be very put off if I were someone trying to gain entry into the language (why dwell on such a minor issue?). However, as both you and I know, most books don't explicitly make this distinction. So, even if I had read the "good" Perl books, the "proper" spelling of Perl could be implied at best.
(that) you aren't aware of the good Perl websites
My previous argument in the grandparent node about the monestary and my statements above about Perl literature should sufficiently address this point.
(that) you aren't familiar with the writings of the good Perl authors and programmers
Where else would good Perl authors and programmers write other than in books and on websites? See previous argments.
or if you know all those things, (that) you either haven't noticed that they all write "Perl", not "PERL", or you don't care.
Except, as stated in another part of this topic, here
It's like misspelling my name or the name of my company in your cover letter. I know what you mean, but it's a silly mistake you could easily have corrected.
Err...not quite. In looking at a lot of the books on my shelf right now, I see a lot of the titles are in all capital letters ("APPLIED COMBINATORICS", "LINEAR ALGEBRA AND ITS APPLICATIONS", "THE ART OF WAR", etc). Does this mean that it's wrong to refer to them in a different capitalization ("Applied Combinatorics", "Linear Algebra and its Applications", "The Art of War")? Moreover, the logo for my company spells out the company name in all capital letters. However, the name of the company is most often refered to in title case. Misspelling is one thing; differing capitalization is another.
And, because I just thought of it, to paraphrase one of the mottoes of the Perl community is "be liberal in what you accept and strict in what you produce". The attitude that "PERL" is absolutely incorrect flies in the face of this somewhat, wouldn't you say?
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