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Comment by Mithaldu | Hacker News Reader

I don't know whether you recognize this as wrong, or are surprised at the thought of such a thing (which doesn't actually exist like that).

In any case, i've suggested a correction here: http://blog.jenkster.com/2015/12/which-programming-languages...

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$_ isn't really global though:

    perl -e 'for (1,2,3,4) { for (5,6) { print "  $_\n" } print "$_\n" }'

It may look like it is not in loop constructs, but it is. `for` and friends just apply `local` scoping to `$_` internally.

I recognize this as wrong, and am surprised by how he could have gotten that idea. Good job with the correction.

Well, try to explain $_ in a short sentence without being wrong. "It's the perl equivalent of the pronoun 'it'." OK, now try explaining it in proper engineering terms that describes exactly what it is, how to use it, and in some sense, how to implement it, in about that many words.

At the very least, I suspect honesty will compel you to admit that either A: that took you longer than you expected or B: you left out a lot of corner cases, especially when modifying $_ does or does not change the thing it does or does not reference, and how it interacts with local, and, and, and....

I did in the linked comment in roughly the same space as the original description. The only thing that could maybe have been included is the scope restriction afforded by local, but that's a feature available to all variables and not necessary to mention.

I also did not take longer than expected, nor did i leave out any corner cases that affect day-to-day work and am not aware of many of them existing in the first palce.

Here you go: default variable to pass string argument to many built-in functions and operators, which typically return their result in the same variable.

Yes, it took a little longer. No, it didn't took that much longer to leave out plainly invalid and misleading description. No, I didn't need to put corner cases there, exactly the same way as you wouldn't specify corner cases for Yacc to describe what it does.

Ok. $_ isn't trivial to understand, let alone explain. But nobody's claiming that. Well not me at least.

What irked me is that's just about all the author's got to say about Perl in the article. Other languages inherited this "feature" (Ruby anyone?) or equivalents, but no mention of that. Why even mention Perl if he's got nothing (solid) to say about it?

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