HN user

peterkelly

10,676 karma

Peter Kelly

Email: kellypmk@gmail.com or peter@pmkelly.net

Twitter: 0xpmkelly

https://www.pmkelly.net

http://blog.uxproductivity.com/

PGP key: http://www.pmkelly.net/pgp-key

Fingerprint: 5435 6718 59F0 DD1F BFA0 5E46 2523 BAA1 44AE 2966

Posts242
Comments1,136
View on HN
www.logosresearch.ai 12d ago

Migrating Code by Proof: From F# to Python

peterkelly
1pts0
web.ist.utl.pt 13d ago

Cpp2Rust: Automatic Translation of C++ to Safe Rust [pdf]

peterkelly
2pts0
www.youtube.com 14d ago

I Taught Myself C by Rejecting Modern Tech [video]

peterkelly
3pts0
www.scummdoc.com 23d ago

Passport to Adventure: The Scumm Story

peterkelly
2pts0
commodore.net 1mo ago

Commodore Callback

peterkelly
35pts4
www.youtube.com 2mo ago

Remembering the Computer Literacy Project (1992) [video]

peterkelly
4pts1
www.youtube.com 4mo ago

Hammond XK-7D [video]

peterkelly
1pts0
www.youtube.com 6mo ago

Only working copy of 50 year old computer program found when cleaning out office [video]

peterkelly
1pts2
www.youtube.com 11mo ago

Vibe Coding Is the Worst Idea of 2025 [video]

peterkelly
5pts1
github.com 11mo ago

Uploading PDF via Files API and using in Streaming gives 400 bad request

peterkelly
1pts0
www.commodore.net 1y ago

Commodore 64 Ultimate

peterkelly
176pts139
www.youtube.com 1y ago

Showing TypeScript's creator DOOM [video]

peterkelly
1pts0
martypc.net 1y ago

MartyPC Web Edition 0.3.0

peterkelly
1pts0
www.youtube.com 1y ago

The Creator of DOS [video]

peterkelly
1pts0
github.com 1y ago

MartyPC: An IBM PC/XT Emulator Written in Rust

peterkelly
1pts0
en.wikipedia.org 1y ago

AI Slop

peterkelly
6pts0
www.youtube.com 1y ago

Operation Binder: Secrets of Inter-Process Communication [video]

peterkelly
2pts0
github.com 1y ago

Sierra Creative Interpreter (SCI) Script Compiler Now Open Source

peterkelly
2pts0
www.cnn.com 1y ago

Couple in an Uber crash can't sue because of an Uber Eats order

peterkelly
4pts2
www.youtube.com 2y ago

Roberta Williams – King's Quest 40th Anniversary [video]

peterkelly
31pts9
www.itnews.com.au 2y ago

UniSuper's Google Cloud environment was deleted

peterkelly
8pts0
junkmailriot.org 2y ago

The Adversarial Process

peterkelly
1pts0
www.youtube.com 2y ago

Abandoned Steam Engine Brought Back to Life [video]

peterkelly
2pts0
twitter.com 3y ago

“I’ve broken some rules to make this ”

peterkelly
18pts1
www.youtube.com 3y ago

A.I. Is B.S

peterkelly
3pts2
qz.com 3y ago

Thailand has found its missing radioactive cylinder

peterkelly
1pts0
www.smh.com.au 3y ago

A rental application service is selling extra data protection for $20

peterkelly
1pts0
arxiv.org 3y ago

Range-Based Set Reconciliation and Authenticated Set Representations

peterkelly
2pts0
www.youtube.com 3y ago

SerenityOS Update (December 2022)

peterkelly
2pts0
www.bbc.com 3y ago

China Covid: Angry protests at giant iPhone factory in Zhengzhou

peterkelly
5pts0

PhD in Computer Science with 15+ years experience bridging the gap between the worlds of compilers/interpreters and scientific & business workflow orchestration systems. The world deserves better languages and developer tooling and it's my mission to continue exploring what's possible.

Location: Chiang Mai, Thailand

Remote: Yes

Willing to relocate: No

Technologies: Compilers, interpreters, language runtimes, distributed systems. Rust, Python, C, C++, TypeScript, Postgres.

Résumé/CV: https://www.pmkelly.net/resume.pdf

Email: peter@pmkelly.net

DAG Workflow Engine 3 months ago

I've always been of the view that for a workflow language, you should use a proper, turing-complete functional language which gives you all the usual flexiblity for transformations on intermediate data, while also supporting things like automatic parallelisation of things like external, compute-intensive tasks.

I recommend checking out https://github.com/peterkelly/rex and also my PhD thesis on the topic https://www.pmkelly.net/publications/thesis.pdf.

The gap in flexiblity between DAG-only and a full language designed for the task is a significant one.

[dead] 9 months ago

Flagged because this takes you to a random website so everyone is going to be reading a different article.

I love Kagi as a search engine, and this is a cool idea, but posting a "random web page selector" without explanation on HN is just confusing.

For some people it's a job.

For others it's a calling.

Nothing wrong with either - I just think it's worth being aware that people have different motivations.

There was a post on HN the other day where someone was launching an email assistant that used AI to summarise emails that you received. The idea didn't excite me, it scared me.

I really wish the tech industry would stop rushing out unreliable misinformation generators like this without regard for the risks.

Google's "AI summaries" are going to get someone killed one day. Especially with regards to sensitive topics, it's basically an autonomous agent that automates the otherwise time-consuming process of defamation.

If there's one thing I definitely don't want AI in the middle of, it's communication with other people. The potential for misunderstandings due to hallucination in summaries, both on my end and the recipient's, scares me. There were some pretty bad examples with Apple News.

Accuracy matters, especially when communicating with customers or between managers/employees, and I can imagine many kinds of scenarios where this goes wrong.

I'm honestly curious why Apple (and other OS vendors like MS and various Linux distributions) still feel the need to tweak their UIs many, many years after having reached maturity.

How many iterations does it take before you get it right?

I get that there's a certain sense of fashion to it, but so often these changes are either neutral or worse, and it just seems so pointless. I don't see any concrete benefits of this year's UI design over what was already there 10-20 years ago.

On Bloat 1 year ago

The author is the co-creator of Go, Plan 9, UTF-8, and the first Unix windowing system.

Whatever you may think of his arguments or slide templates, I don't think "innocent bystander" is an accurate label.

There's certainly a tradeoff between the two approaches; a simpler representation (list of tasks or DAG) is easier to query and manipulate, at the cost of being less expressive, lacking features like loops, conditionals, etc.

In the workflow engine I described, state is represented as a graph of objects in memory; this includes values like integers/strings and data structures like dictionaries/lists, as well as closures, environments, and the execution stack. This graph is serialised as JSON and stored in a postgres table. A more compact binary representation could be added in the future if performance requirements demand it, but JSON has been sufficient for our needs so far. A delta between each snapshot is also stored in an execution log, so that the complete execution history is stored for auditing purposes.

The interpreter is written in such a way that all object allocation, object manipulation, and garbage collection is under its control, and all the data needed to represent execution state is stored in a manner that can be easily serialised. In particular, we avoid the use of pointers to memory locations, instead using object ids for all references. So the persistent state, when loaded, can be accessed directly, since any time a reference from one object to another needs to be followed, the interpreter does so by looking up the object in the heap based on its id.

Non-deterministic and blocking operations (including IPC receives) are handled outside of the evaluation cycle. This enables their results to be explicitly captured in the execution log, and allows for retries to be handled by an external mechanism under control of the user (since retrying can be unsafe if the operation is not idempotent).

The biggest win of using a proper language for expressing the workflow is the ability to add arbitrary logic between blocking operations, such as conditional tests or data structure manipulation. Any kind of logic you might want to do can be expressed due to the fact the workflow language is Turing-complete.

Durable execution is best done at the level of a language implementation, not as a library.

A workflow engine I recently built provided an interpreter for a Scheme-based language that, for each blocking operation, took a snapshot of the interpreter state (heap + stack) and persisted that to a database. Each time an operation completes (which could be after hours/days/weeks), the interpreter state is restored from the database and execution proceeds from the point at which it was previously suspended. The interpreter supports concurrency, allowing multiple blocking operations to be in progress at the same time, so the work to be done after the completion of one can proceed even while others remain blocked.

The advantage of doing this at the language level is that persistence becomes transparent to the programmer. No decorators are needed; every function and expression inherently has all the properties of a "step" as described here. Deterministic execution can be provided if needed. And if there's a need to call out to external code, it is possible to expose Python functions as Scheme built-ins that can be invoked from the interpreter either synchronously or asynchronously.

I see a lot of workflow engines released that almost get to the point of being like a traditional programming language interpreter but not quite, exposing the structure of the workflow using a DAG with explicit nodes/edges, or (in the case of DBOS) as decorators. While I think this is ok for some applications, I really believe the "workflow as a programming language" perspective deserves more attention.

There's a lot of really interesting work that's been done over the years on persistent systems, and especially orthogonal persistence, but sadly this has mostly remained confined to the research literature. Two real-world systems that do implement persistence at the language level are Ethereum and Smalltalk; also some of the older Lisp-based systems provided similar functionality. I think there's a lot more value waiting to be mined from these past efforts.

A PhD is a program to compete for academic prestige

That's true for some people but others have different motivations, such as learning useful skills so they can gain the ability to work on interesting problems in a given field.

Doing a PhD in PL can also help you get the kind of jobs you mentioned, and achieve more once you're there. For me, the most valuable I thing I got out of the process was extensive exposure to the literature, which has been useful in a range of contexts.

One of the most important papers in software engineering, which I believe everyone in this profession should read and internalize.

Every time I see another startup trying use LLMs for code generation I sigh in despair. As AI technology improves and becomes better at producing code, what looks like a win in the short term will end up creating more and more code that has been created without a human going through the necessary thought processes and problem solving steps to build the theory of the software as described in this paper.

It's also why its critically important for companies to do what they can to retain the people who built the software in the first place, or at least ensure there's enough continuity as new people join the team so they can build their mental model by working alongside the original developers.

Why not debate the points in the article on their own merits? Which parts do you agree or disagree with, and why?