This is kind of illustrative of the '60s acid trip that perpetuates in programming "Everything's a string maaaaan". The output is seen as truth because the representation is for some reason too hard to get at or too hard to cascade through the system. There's a total comedy of work going on in the unix way of a wc pipeline versus calling a length function on a list. Nonetheless, the unix pipeline was and is often magnitude easier for a single user to get at. This kind of thing is amusing and endearing to me about our profession in modern day. Regards, Kevin On Sun, Jan 12, 2020 at 9:57 AM Warner Losh <imp(a)bsdimp.com> wrote:

Kevin Bowling writes: Can you please elaborate? I read your post, and while I can see that it contains English words I can't make any sense out of what you said. Thanks, Jon

Kevin Bowling writes: I wasn't being snarky. You said "The output is seen as truth because the representation is for some reason too hard to get at or too hard to cascade through the system." I honestly have no idea what that means. Likewise, "There's a total comedy of work going on in the unix way of a wc pipeline versus calling a length function on a list." I just don't know what you mean. Jon

Kevin Bowling writes: OK, I have trouble correlating this with your original post but I think that I understand it well enough to comment. I agree that it is a problem that very few people understand what's going on inside anything today from a toaster to a computer. On the computer end of things this concerns me a lot and improving the quality of education in this area is one of my main late-in-life missions. I'm under the illusion that I've helped some based on comments that I've received from people who have tracked me down and let me know how much the information in my book helped them. On to your example... If I had a grocery list on a piece of paper I would count the lines because I don't number my grocery lists. I'm going to guess that few people do. So, I would count the lines in my head and remember the result. This is pretty much equivalent to what happens when something is piped into wc. I don't see much difference between a and b in your example. That's because when I count up the number of lines in the list, I am making a temporary copy of the list in my head and then forgetting what was on the list (which may account for the late night trip to the grocery store a couple of days ago). So I think that the point that you're trying to make, correct me if I'm wrong, is that if lists just knew how long they were you could just ask and that it would be more efficient. While that may be true, it sort of assume that this is something so common that the extra overhead for line counting should be part of every list. And it doesn't address the issue that while maybe you want a line count I may want a character count or a count of all lines that begin with the letter A. Limiting this example to just line numbers ignores the fact that different people might want different information that can't all be predicted in advance and built into every program. It also seems to me that the root problem here is that the data in the original example was in an emacs-specific format instead of the default UNIX text file format. The beauty of UNIX is that with a common file format one can create tools that process data in different ways that then operate on all data. Yes, it's not as efficient as creating a custom tool for a particular purpose, but is much better for casual use. One can always create a special purpose tool if a particular use becomes so prevalent that the extra efficiency is worthwhile. If you're not familiar with it, find a copy of the Communications of the ACM issue where Knuth presented a clever search algorithm (if I remember correctly) and McIlroy did a critique. One of the things that Doug pointed out what that while Don's code was more efficient, by creating a new pile of special-purpose code he introduced bugs. Many people have claimed, incorrectly in my opinion, that this model fails in the modern era because it only works on text data. They change the subject when I point out that ImageMagick works on binary data. And, there are now stream processing utilities for JSON data and such that show that the UNIX model still works IF you understand it and know how to use it. I don't agree with your closing comment about "most programming bugs". Do you have any data to support this or is it just an opinion? My opinion is that most programming bugs today result from total incompetence as one can prety much get a computer science degree today without every learning that programs run on computers or what a computer is. That's something I'm trying to change, but it's probably a lost cause. A long topic, and not necessarily appropriate for this list. Jon

Bakul Shah writes: Ah. So lines IS the structure that a lot of people want. As I just said in a post, the JSON tools are a good example of communicating structured data although I would have done them differently. Jon