Jonathan Aldrich

YouTube video by Jonathan Aldrich PLP 5.1: The Memory Hierarchy

PLP 5.1: The Memory Hierarchy - youtu.be/FD0XVnNE1u0

Also check out the whole Programming Language Pragmatics playlist: tinyurl.com/PLP5vids

Language implementers need a solid grounding in processor architecture in order to understand how to generate good code. In my latest Programming Language Pragmatics video, I put on my "architecture hat" to cover the memory hierarchy and explain the implications for code generation.

Nice, thanks for the explanation! Now I need to sit down with a couple of linear functions and see how this (matmul = function composition) works. 😀

LOL I never got anything BUT the formulaic matmul (at least, nothing that stuck). Is there a nice explanation of this outside the precalc book?

Some real Nazi thought policing there: "people should not be coming to the Super Bowl unless they're law-abiding Americans who love this country."

“Terrible things are happening outside. Poor helpless people are being dragged out of their homes. Families are torn apart. Men, women, and children are separated. Children come home from school to find that their parents have disappeared.”

Diary of Anne Frank
January 13, 1943

YouTube video by Jonathan Aldrich PLP 4.5 - Semantic Properties of Languages: Soundness

Watch PLP 4.5 - Semantic Properties of Languages: Soundness - youtu.be/UQXVOj9olw4

Also check out the whole Programming Language Pragmatics playlist: tinyurl.com/PLP5vids

And as always, there's even more in the book! amzn.to/4kuKSY2 (Amazon affiliate link)

How do we know that the semantics of a programming language are right?

My latest Programming Language Pragmatics video covers type soundness: the static and dynamic semantics of a language fit together, so that if a program type checks, it will not experience unexpected type errors when it runs.

YouTube video by ALICE Productions You Better Know | A Dance Visual

Check out "You Better Know," the latest dance visual by my eldest, Seal Aldrich!

www.youtube.com/watch?v=KIUh...

Thanks--ACM is working towards tools that can be run as part of reviewing to check for tortured phrases, as well as other potentially problematic indicators. I agree, it can't come too soon!

YouTube video by Jonathan Aldrich PLP 4.4 part 3: Code Transformation

PLP 4.4 part 3: Code Transformation - youtu.be/RWWeUPuXFk4

Also check out the whole Programming Language Pragmatics playlist: tinyurl.com/PLP5vids

In addition to checking for typing and other errors, semantic analysis may transform the representation of the program. In today's Programming Language Pragmatics video, I describe how one such transformation, the constant propagation optimization, can be specified using rewriting rules.

In celebration of #HispanicHeritageMonth, ACM is highlighting Trilce Estrada.
Trilce Estrada is an Associate Professor and Director of the Data Science Laboratory at the University of New Mexico. Her interests are machine learning, big data and their applications to interdisciplinary problems.

I'd definitely invite you to do so! The ACM is far from perfect, but it's become more responsive recently, and a lot of good things are happening: fully Open Access publishing, a strategic AI Summit in the works for next year, support and advocacy for computing research and practice.

Is there an obvious Trump real estate angle? Yes, of course. But the big picture is stopping the war and giving Gaza a chance to rebuild and eventually form their own nation. The plan does that, if it succeeds.

For what it's worth, ACM is looking at adopting the particular policy you mention. You do have a point that it is a way of increasing public pressure on an organization.

Yes, ACM wants to be a part of COPE. Doing so does not require it to follow all of COPE's recommendations. Honestly, I have no idea why you think this is such a big deal. If the problem is with an ACM paper, people can just report it to the ACM!

Here’s the full text of Trump’s 20-point plan to end Israel’s war on Gaza The White House says its proposal would end the war on Gaza immediately if both sides accept.

It's *actually* a good plan! I hope, for the sake of Gazans, Israelis, and the world, that it works.

www.aljazeera.com/news/2025/9/...

The "Words Matter" site was put together by ACM volunteers, it was not a staff initiative, so your complaint is misplaced.

Current ACM policy is that issues with ACM publications should be reported directly to ACM. That may change at some point, but it doesn't seem unreasonable.

Nothing is banned. This page is advisory only. If you disagree with it, you can continue to use the word Byzantine.

Personally, if I ever publish about Byzantine fault tolerance, I'll use the word. But, I've stopped using master for the main branch on github; main works better & doesn't offend.

Many organizations are changing their language and policies surrounding DEI. The ACM has not, we are sticking to our principles.

- Yannis Ioannidis, ACM president, today

I'm proud to be a member & volunteer for the @acm.org!

I'll give a short overview of the MSE and then answer questions. I hope to see you! To attend the virtual information session, register at:

admissions.scs.cmu.edu/register/mse...

In addition to the overview on Wednesday, there's an application workshop Friday at 1pm (same link to register).

Interested in taking your software development career to the next level? I'm hosting an information session for CMU's Master of Software Engineering programs this Wednesday October 1st, 1pm EDT. We focus on training leaders in SE, and our graduates' records prove that it works!🧵

Programming Language Pragmatics Talks - YouTube Programming languages are the programmer's most basic tool. The textbook Programming Language Pragmatics, 5th edition (affiliate link: https://amzn.to/4kuKSY...

This is just one part of my Programming Language Pragmatics playlist: tinyurl.com/PLP5vids

And as always, there's more details in the book! amzn.to/4kuKSY2 (Amazon affiliate link)

YouTube video by Jonathan Aldrich PLP 4.4 part 2: Implementing Type Checkers

We discuss how to adapt typing environments to a symbol table, and how to handle errors in a way that avoids reporting duplicate error messages to the user.

PLP 4.4 part 2: Implementing Type Checkers - youtu.be/x1nIVjrc-EI

How does one implement a type checker?

My latest Programming Language Pragmatics video discusses how a type checker, like an interpreter, traverses the AST of a program, implementing the functionality of the typing rule for each AST form.

Picture of me on a morning run with a sign, Pevensey Road

Ever wonder where Peter, Susan, Edmund, and Lucy lived before the war and Narnia? I think I found it!

Programming Language Pragmatics Talks - YouTube Programming languages are the programmer's most basic tool. The textbook Programming Language Pragmatics, 5th edition (affiliate link: https://amzn.to/4kuKSY...

Also check out the whole Programming Language Pragmatics playlist: tinyurl.com/PLP5vids

And as always, there's even more in the book! amzn.to/4kuKSY2 (Amazon affiliate link)

YouTube video by Jonathan Aldrich PLP 4.4 part 1: Static Semantics and Typing Rules

Static type checking is awesome! It can find errors at compile time, ensures that type annotations are correct, and helps generate efficient code. In today's Programming Language Pragmatics video, we formalize type checking for expressions and statements with inference rules.

youtu.be/Lv-JlRkk3pY