A Browser Approach To Parsing

June 26, 2023 by Al Williams 3 Comments

There are few rites of programmer passage as iconic as writing your first parser. You might want to interpret or compile a scripting language, or you might want to accept natural-language-like commands. You need a parser. [Varunramesh] wants to show you parser combinators, a technique used to make practical parsers. But the demonstration using interactive code cells in the web page is nearly as interesting as the technique.

Historically, you parse tokens, and this technique can do that too, but it can also operate directly on character streams if you prefer. The idea is related to recursive descent parsing, where you attempt to parse certain things, and if those things fail, you try again.

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How Hardware Testing Got Plugged Into A Continuous Integration Framework

June 26, 2023 by Donald Papp 5 Comments

The concept of Continuous Integration (CI) is a powerful tool in software development, and it’s not every day we get a look at how someone integrated automated hardware testing into their system. [Michael Orenstein] brought to our attention the Hardware CI Arena, a framework for doing exactly that across a variety of host OSes and microcontroller architectures.

The Hardware CI Arena allows testing software across a variety of hardware boards such as Arduino, RP2040, ESP32, and more.

Here’s the reason it exists: while in theory every OS and piece of hardware implements things like USB communications and device discovery in the same way, in practice that is not always the case. For individual projects, the edge cases (or even occasional bugs) are not much of a problem. But when one is developing a software product that aims to work seamlessly across different hardware options, such things get in the way. To provide a reliable experience, one must find and address edge cases.

The Hardware CI Arena (GitHub repository) was created to allow automated testing to be done across a variety of common OS and hardware configurations. It does this by allowing software-controlled interactions to a bank of actual, physical hardware options. It’s purpose-built for a specific need, but the level of detail and frank discussion of the issues involved is an interesting look at what it took to get this kind of thing up and running.

The value of automatic hardware testing with custom rigs is familiar ground to anyone who develops hardware, but tying that idea into a testing and CI framework for a software product expands the idea in a useful way. When it comes to identifying problems, earlier is always better.

In Praise Of RPN (with Python Or C)

June 21, 2023 by Al Williams 39 Comments

HP calculators, slide rules, and Forth all have something in common: reverse polish notation or RPN. Admittedly, slide rules don’t really have RPN, but you work problems on them the same way you do with an RPN calculator. For whatever reason, RPN didn’t really succeed in the general marketplace, and you might wonder why it was ever a thing. The biggest reason is that RPN is very easy to implement compared to working through proper algebraic, or infix, notation. In addition, in the early years of computers and calculators, you didn’t have much to work with, and people were used to using slide rules, so having something that didn’t take a lot of code that matched how users worked anyway was a win-win.

What is RPN?

If you haven’t encountered RPN before, it is an easy way to express math without ambiguity. For example, what’s 5 + 3 * 6? It’s 23 and not 48. By order of operations you know that you have to multiply before you add, even if you wrote down the multiplication second. You have to read through the whole equation before you can get started with math, and if you want to force the other result, you’ll need parentheses.

With RPN, there is no ambiguity depending on secret rules or parentheses, nor is there any reason to remember things unnecessarily. For instance, to calculate our example you have to read all the way through once to figure out that you have to multiply first, then you need to remember that is pending and add the 5. With RPN, you go left to right, and every time you see an operator, you act on it and move on. With RPN, you would write 3 6 * 5 +.

While HP calculators were the most common place to encounter RPN, it wasn’t the only place. Friden calculators had it, too. Some early computers and calculators supported it but didn’t name it. Some Soviet-era calculators used it, too, including the famous Elektronika B3-34, which was featured in a science fiction story in a Soviet magazine aimed at young people in 1985. The story set problems that had to be worked on the calculator.

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Too Much Git? Try Gitless

June 18, 2023 by Bryan Cockfield 48 Comments

Git has been a powerful tool for software development and version control since the mid ’00s, gaining widespread popularity since then. Originally built by none other than Linus Torvalds for handling Linux kernel development, it’s branched out for use with all kinds of other projects. That being said, it is not the easiest thing to learn how to use, with tons of options, abstract ideas, and non-linear workflows to keep track of. So if you’re new to the system or don’t need all of its vast swath of features, you might want to try out an alternative like Gitless.

Thanks to the fact that the original Git is open source, it’s free to modify and use as any user sees fit, and there are plenty of options available. This one aims to simplify many of the features found in the original Git, implementing a tracking system which somewhat automates commits. It also includes a simplified branching system, making it easier to switch between branches and keep better track of all that’s happening in a project. The command line interface is simplified as well, and the entire system is backwards-compatible with Git which means that if you find yourself needing some of the more advanced tools it’s possible to switch between them with relative ease.

For those of us keeping track of our own software projects, who don’t necessarily need the full feature set that the original Git has to offer, this could be a powerful tool that decreases the steep learning curve that Git is known for. It’s definitely a system work diving into, though, regardless of whichever implementation you choose. It’s an effective tool for everything from complex, professional projects to small hobby projects on the Arduino.

The First Search Engines, Built By Librarians

June 11, 2023 by Bryan Cockfield 14 Comments

Before the Internet became the advertisement generator we know and love today, interspersed with interesting information here and there, it was originally a network of computers largely among various universities. This was even before the world-wide web and HTML which means that the people using these proto-networks, mostly researchers and other academics, had to build things we might take for granted from the ground up. One of those was one of the first search engines, built by the librarians who were cataloging all of the research in their universities, and using their relatively primitive computer networks to store and retrieve all of this information.

This search engine was called SUPARS, the Syracuse University Psychological Abstracts Retrieval Service. It was originally built for psychology research papers, and perhaps unsurprisingly the psychologists at the university also used this new system as the basis for understanding how humans would interact with computers. This was the 1970s after all, and most people had never used a computer, so documenting how they used search engine led to some important breakthroughs in the way we think about the best ways of designing systems like these.

The search engine was technically revolutionary for the time as well. It was among the first to allow text to be searched within documents and saved previous searches for users and researchers to access and learn from. The experiment was driven by the need to support researchers in a future where reference librarians would need assistance dealing with more and more information in their libraries, and it highlighted the challenges of vocabulary control in free-text searching.

The visionaries behind SUPARS recognized the changing landscape of research and designed for the future that would rely on networked computer systems. Their contributions expanded the understanding of how technology could shape human communication and effectiveness, and while they might not have imagined the world we are currently in, they certainly paved the way for the advances that led to its widespread adoption even outside a university setting. There were some false starts along that path, though.

What Do You Want In A Programming Assistant?

June 10, 2023 by Al Williams 57 Comments

The Propellerheads released a song in 1998 entitled “History Repeating.” If you don’t know it, the lyrics include: “They say the next big thing is here. That the revolution’s near. But to me, it seems quite clear. That it’s all just a little bit of history repeating.” The next big thing today seems to be the AI chatbots. We’ve heard every opinion from the “revolutionize everything” to “destroy everything” camp. But, really, isn’t it a bit of history repeating itself? We get new tech. Some oversell it. Some fear it. Then, in the end, it becomes part of the ordinary landscape and seems unremarkable in the light of the new next big thing. Dynamite, the steam engine, cars, TV, and the Internet were all predicted to “ruin everything” at some point in the past.

History really does repeat itself. After all, when X-rays were discovered, they were claimed to cure pneumonia and other infections, along with other miracle cures. Those didn’t pan out, but we still use them for things they are good at. Calculators were going to ruin math classes. There are plenty of other examples.

This came to mind because a recent post from ACM has the contrary view that chatbots aren’t able to help real programmers. We’ve also seen that — maybe — it can, in limited ways. We suspect it is like getting a new larger monitor. At first, it seems huge. But in a week, it is just the normal monitor, and your old one — which had been perfectly adequate — seems tiny.

But we think there’s a larger point here. Maybe the chatbots will help programmers. Maybe they won’t. But clearly, programmers want some kind of help. We just aren’t sure what kind of help it is. Do we really want CoPilot to write our code for us? Do we want to ask Bard or ChatGPT/Bing what is the best way to balance a B-tree? Asking AI to do static code analysis seems to work pretty well.

So maybe your path to fame and maybe even riches is to figure out — AI-based or not — what people actually want in an automated programming assistant and build that. The home computer idea languished until someone figured out what people wanted to do with them. Video cassette didn’t make it into the home until companies figured out what people wanted most to watch on them.

How much and what kind of help do you want when you program? Or design a circuit or PCB? Or even a 3D model? Maybe AI isn’t going to take your job; it will just make it easier. We doubt, though, that it can much improve on Dame Shirley Bassey’s history lesson.

Contrary View: Chatbots Don’t Help Programmers

June 8, 2023 by Al Williams 67 Comments

[Bertrand Meyer] is a decided contrarian in his views on AI and programming. In a recent Communications of the ACM blog post, he reveals that — unlike many others — he thinks AI in its current state isn’t very useful for practical programming. He was responding, in part, to another article from the ACM entitled “The End of Programming,” which, like many other articles, is claiming that, soon, no one will write software the way we do and have done for the last few decades. You can see [Matt Welsh] describe his thoughts on this in the video below. But [Bertrand] disagrees.

As we have also noted, [Bretrand] says:

“AI in its modern form, however, does not generate correct programs: it generates programs inferred from many earlier programs it has seen. These programs look correct but have no guarantee of correctness.”

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