Simon Willison's Weblog: programming-languages

Typing without having to type

2026-02-18T18:56:56+00:00

25+ years into my career as a programmer I think I may finally be coming around to preferring type hints or even strong typing. I resisted those in the past because they slowed down the rate at which I could iterate on code, especially in the REPL environments that were key to my productivity. But if a coding agent is doing all that typing for me, the benefits of explicitly defining all of those types are suddenly much more attractive.

Tags: programming, programming-languages, static-typing, ai-assisted-programming

jordanhubbard/nanolang

2026-01-19T23:58:56+00:00

jordanhubbard/nanolang

Plenty of people have mused about what a new programming language specifically designed to be used by LLMs might look like. Jordan Hubbard (co-founder of FreeBSD, with serious stints at Apple and NVIDIA) just released exactly that.

A minimal, LLM-friendly programming language with mandatory testing and unambiguous syntax.

NanoLang transpiles to C for native performance while providing a clean, modern syntax optimized for both human readability and AI code generation.

The syntax strikes me as an interesting mix between C, Lisp and Rust.

I decided to see if an LLM could produce working code in it directly, given the necessary context. I started with this MEMORY.md file, which begins:

Purpose: This file is designed specifically for Large Language Model consumption. It contains the essential knowledge needed to generate, debug, and understand NanoLang code. Pair this with spec.json for complete language coverage.

I ran that using LLM and llm-anthropic like this:

llm -m claude-opus-4.5 \
  -s https://raw.githubusercontent.com/jordanhubbard/nanolang/refs/heads/main/MEMORY.md \
  'Build me a mandelbrot fractal CLI tool in this language' 
  > /tmp/fractal.nano

The resulting code... did not compile.

I may have been too optimistic expecting a one-shot working program for a new language like this. So I ran a clone of the actual project, copied in my program and had Claude Code take a look at the failing compiler output.

... and it worked! Claude happily grepped its way through the various examples/ and built me a working program.

Here's the Claude Code transcript - you can see it reading relevant examples here - and here's the finished code plus its output.

I've suspected for a while that LLMs and coding agents might significantly reduce the friction involved in launching a new language. This result reinforces my opinion.

Via Hacker News

Tags: programming-languages, ai, generative-ai, llms, ai-assisted-programming, llm, coding-agents, claude-code

Prediction: AI will make formal verification go mainstream

2025-12-09T03:11:19+00:00

Prediction: AI will make formal verification go mainstream

Martin Kleppmann makes the case for formal verification languages (things like Dafny, Nagini, and Verus) to finally start achieving more mainstream usage. Code generated by LLMs can benefit enormously from more robust verification, and LLMs themselves make these notoriously difficult systems easier to work with.

The paper Can LLMs Enable Verification in Mainstream Programming? by JetBrains Research in March 2025 found that Claude 3.5 Sonnet saw promising results for the three languages I listed above.

Via lobste.rs

Tags: predictions, programming-languages, ai, generative-ai, llms, ai-assisted-programming, martin-kleppmann

Thoughts on Go vs. Rust vs. Zig

2025-12-05T04:28:05+00:00

Thoughts on Go vs. Rust vs. Zig

Thoughtful commentary on Go, Rust, and Zig by Sinclair Target. I haven't seen a single comparison that covers all three before and I learned a lot from reading this.

One thing that I hadn't noticed before is that none of these three languages implement class-based OOP.

Via Hacker News

Tags: go, object-oriented-programming, programming-languages, rust, zig

Could LLMs encourage new programming languages?

2025-11-07T16:00:42+00:00

My hunch is that existing LLMs make it easier to build a new programming language in a way that captures new developers.

Most programming languages are similar enough to existing languages that you only need to know a small number of details to use them: what's the core syntax for variables, loops, conditionals and functions? How does memory management work? What's the concurrency model?

For many languages you can fit all of that, including illustrative examples, in a few thousand tokens of text.

So ship your new programming language with a Claude Skills style document and give your early adopters the ability to write it with LLMs. The LLMs should handle that very well, especially if they get to run an agentic loop against a compiler or even a linter that you provide.

This post started as a comment.

Tags: hacker-news, programming-languages, ai, generative-ai, llms, ai-assisted-programming, coding-agents, skills

Quoting Steve Francia

2025-11-04T02:54:07+00:00

Every time an engineer evaluates a language that isn’t “theirs,” their brain is literally working against them. They’re not just analyzing technical trade offs, they’re contemplating a version of themselves that doesn’t exist yet, that feels threatening to the version that does. The Python developer reads case studies about Go’s performance and their amygdala quietly marks each one as a threat to be neutralized. The Rust advocate looks at identical problems and their Default Mode Network constructs narratives about why “only” Rust can solve them.

We’re not lying. We genuinely believe our reasoning is sound. That’s what makes identity based thinking so expensive, and so invisible.

— Steve Francia, Why Engineers Can't Be Rational About Programming Languages

Tags: programming-languages, psychology, technical-debt

Geoffrey Huntley is cursed

2025-09-09T09:31:21+00:00

I ran Claude in a loop for three months, and it created a genz programming language called cursed

Geoffrey Huntley vibe-coded an entirely new programming language using Claude:

The programming language is called "cursed". It's cursed in its lexical structure, it's cursed in how it was built, it's cursed that this is possible, it's cursed in how cheap this was, and it's cursed through how many times I've sworn at Claude.

Geoffrey's initial prompt:

Hey, can you make me a programming language like Golang but all the lexical keywords are swapped so they're Gen Z slang?

Then he pushed it to keep on iterating over a three month period.

Here's Hello World:

vibe main
yeet "vibez"

slay main() {
    vibez.spill("Hello, World!")
}

And here's binary search, part of 17+ LeetCode problems that run as part of the test suite:

slay binary_search(nums normie[], target normie) normie {
    sus left normie = 0
    sus right normie = len(nums) - 1    
    bestie (left <= right) {
        sus mid normie = left + (right - left) / 2
        ready (nums[mid] == target) {
            damn mid
        }
        ready (nums[mid] < target) {
            left = mid + 1
        } otherwise {
            right = mid - 1
        }
    }
    damn -1
}

This is a substantial project. The repository currently has 1,198 commits. It has both an interpreter mode and a compiler mode, and can compile programs to native binaries (via LLVM) for macOS, Linux and Windows.

It looks like it was mostly built using Claude running via Sourcegraph's Amp, which produces detailed commit messages. The commits include links to archived Amp sessions but sadly those don't appear to be publicly visible.

The first version was written in C, then Geoffrey had Claude port it to Rust and then Zig. His cost estimate:

Technically it costs about 5k usd to build your own compiler now because cursed was implemented first in c, then rust, now zig. So yeah, it’s not one compiler it’s three editions of it. For a total of $14k USD.

Via @GeoffreyHuntley

Tags: c, programming-languages, ai, rust, zig, generative-ai, llms, ai-assisted-programming, anthropic, claude, vibe-coding, geoffrey-huntley

Quoting Paul Biggar

2025-06-16T17:56:57+00:00

In conversation with our investors and the board, we believed that the best way forward was to shut down the company [Dark, Inc], as it was clear that an 8 year old product with no traction was not going to attract new investment. In our discussions, we agreed that continuity of the product [Darklang] was in the best interest of the users and the community (and of both founders and investors, who do not enjoy being blamed for shutting down tools they can no longer afford to run), and we agreed that this could best be achieved by selling it to the employees.

— Paul Biggar, Goodbye Dark Inc. - Hello Darklang Inc.

Tags: entrepreneurship, programming-languages, startups

Directive prologues and JavaScript dark matter

2025-06-02T18:30:31+00:00

Directive prologues and JavaScript dark matter

Tom MacWright does some archaeology and describes the three different magic comment formats that can affect how JavaScript/TypeScript files are processed:

"a directive"; is a directive prologue, most commonly seen with "use strict";.

/** @aPragma */ is a pragma for a transpiler, often used for /** @jsx h */.

//# aMagicComment is usually used for source maps - //# sourceMappingURL=<url> - but also just got used by v8 for their new explicit compile hints feature.

Via Jim Nielsen

Tags: javascript, programming-languages, v8, typescript, tom-macwright

Quoting Steve Dower

2025-04-12T03:32:14+00:00

Backticks are traditionally banned from use in future language features, due to the small symbol. No reader should need to distinguish ` from ' at a glance.

— Steve Dower, CPython core developer, August 2024

Tags: programming-languages, python

Mojo may be the biggest programming advance in decades

2023-05-04T04:41:03+00:00

Mojo may be the biggest programming advance in decades

Jeremy Howard makes a very convincing argument for why the new programming language Mojo is a big deal.

Mojo is a superset of Python designed by a team lead by Chris Lattner, who previously created LLVM, Clang and and Swift.

Existing Python code should work unmodified, but it also adds features that enable performant low-level programming—like “fn” for creating typed, compiled functions and “struct” for memory-optimized alternatives to classes.

It’s worth watching Jeremy’s video where he uses these features to get more than a 2000x speed up implementing matrix multiplication, while still keeping the code readable and easy to follow.

Mojo isn’t available yet outside of a playground preview environment, but it does look like an intriguing new project.

Via @hamelhusain

Tags: programming-languages, python, ai, mojo, jeremy-howard

Cyber

2023-01-28T04:25:17+00:00

Cyber

“Cyber is a new language for fast, efficient, and concurrent scripting.” Lots of interesting ideas in here, but the one that really caught my eye is that its designed to be easily embedded into other languages and “will allow the host to insert gas mileage checks in user scripts. This allows the host to control how long a script can run”—my dream feature for implementing a safe, sandboxed extension mechanism! Cyber is implemented using Zig and LLVM.

Via lobste.rs

Tags: llvm, programming-languages, sandboxing, zig

jq language description

2022-04-26T19:04:09+00:00

jq language description

I love jq but I’ve always found it difficult to remember how to use it, and the manual hasn’t helped me as much as I would hope. It turns out the jq wiki on GitHub offers an alternative, more detailed description of the language which fits the way my brain works a lot better.

Via psacawa on Hacker News

Tags: documentation, programming-languages, jq

Programmer migration patterns

2019-03-28T04:59:16+00:00

Programmer migration patterns

Avery Pennarun explores the history of modern programming languages and how developers have migrated from one to another over time. Lots of fun insights in this.

Tags: programming-languages

String length - Rosetta Code

2019-02-22T15:27:31+00:00

String length - Rosetta Code

Calculating the length of a string is surprisingly difficult once Unicode is involved. Here's a fascinating illustration of how that problem can be attached dozens of different programming languages. From that page: the string "J̲o̲s̲é̲" ("J\x{332}o\x{332}s\x{332}e\x{301}\x{332}") has 4 user-visible graphemes, 9 characters (code points), and 14 bytes when encoded in UTF-8.

Via @jeffsonstein

Tags: programming-languages, strings, unicode

An Early History of Pony

2017-12-18T20:33:54+00:00

An Early History of Pony

Pony is an interesting looking new programming language, built around actor-based concurrency on top of a mathematically proved type system. The history of the language makes for interesting reading: it’s based on experience with actor libraries in C at an investment bank, combined with research into type systems at Imperial College London.

Tags: computer-science, pony, programming-languages

Are traditional web frameworks and languages like RubyOnRail, Spring Boot and PHP dying now when new fast reactive pure JavaScript frameworks and services like Meteor, Node, Angular 2.0 and Firebase are breaking ground?

2015-05-24T09:33:00+00:00

My answer to Are traditional web frameworks and languages like RubyOnRail, Spring Boot and PHP dying now when new fast reactive pure JavaScript frameworks and services like Meteor, Node, Angular 2.0 and Firebase are breaking ground? on Quora

No.

Tags: django, frameworks, java, javascript, programming, programming-languages, web-development, quora

Have you ever experienced a boost in productivity by switching to a different programming language?

2014-03-19T18:38:00+00:00

My answer to Have you ever experienced a boost in productivity by switching to a different programming language? on Quora

Switching from PHP to Python (over a decade ago now) dramatically improved my productivity as a programmer.

Tags: productivity, programming, programming-languages, quora

In simple terms, what is node.js?

2014-01-22T12:48:00+00:00

My answer to In simple terms, what is node.js? on Quora

It's server-side programming, like PHP. The language you write the server-side code in is JavaScript (specifically the JavaScript version supported by Google's V8 JavaScript engine, which was originally written for the Chrome web browser).

Tags: javascript, nodejs, programming-languages, web-development, quora

What are some good resources to learn how to cleanse data using Python?

2013-12-18T11:25:00+00:00

My answer to What are some good resources to learn how to cleanse data using Python? on Quora

http://gnosis.cx/TPiP/ "Text Processing in Python" is a free online book that covers a bunch of useful topics related to data cleanup. It's over 10 years old now but is still mostly relevant - the chapter on regular expressions is particularly good.

Tags: django, programming-languages, python, quora

Why doesn't Google use their resources to improve coding languages?

2013-11-24T17:31:00+00:00

My answer to Why doesn't Google use their resources to improve coding languages? on Quora

Google invest vast resources in to language improvements, and have been doing so for over a decade now. Just off the top of my head...

They have employed many of the Python core team (including creator Guido van Rossum) and supported their work on Python
Their Android team wrote and support an entirely new open source JVM, called Dalvik
They sponsored one of the creators of C to create a brand new systems programming language, Go.
They sponsored major improvements to HTML, including the WHAT-WG which was crucial to the creation of HTML5.
Many of their employees work full time contributing to international standards groups.
As part of Chrome they supported the creation of V8, an astonishingly powerful JIT JavaScript implementation which sparked enormous improvements across rival engines. V8 is also the core of Node.js
Through Google Summer of Code they financially support projects that benefit dozens of open source languages, libraries and frameworks

That's just the stuff I can think if without doing any additional research - it's the tip of the iceberg.

Tags: google, java, programming, programming-languages, web-development, quora

Why do programmers tend to fall in love with non-mainstream languages?

2013-10-19T09:48:00+00:00

My answer to Why do programmers tend to fall in love with non-mainstream languages? on Quora

Just because something is popular doesn't mean it's right for every person, every problem or every situation. If no one ever explored non-mainstream options, better solutions would never be discovered.

Tags: programmers, programming, programming-languages, quora

Web app: what programming knowledge do I need to create a goings on app?

2013-08-07T18:42:00+00:00

My answer to Web app: what programming knowledge do I need to create a goings on app? on Quora

For this kind of application a much more important question than "how can I build it? is "where will I get the data from?" - If you don't have a good answer for that building the app is a waste of your time. The world is littered with local events listings apps that no one uses because they don't have good data.

Tags: google-maps, mobileweb, programming-languages, python, quora

Beginner JavaScript: more code or quality code?

2013-08-06T16:48:00+00:00

My answer to Beginner JavaScript: more code or quality code? on Quora

Write more code. The more code you have written, the better you'll be able to understand why certain techniques for creating higher quality code are worthwhile later on.

If you've never dealt with a horrible tangle of spaghetti code of your own making you'll never be able to truly appreciate good code when you finally write it!

Tags: javascript, programming-languages, quora

In which programming language do programmers get paid the most?

2013-07-06T17:27:00+00:00

My answer to In which programming language do programmers get paid the most? on Quora

The best (and best paid) software engineers work in multiple languages, and pick new ones up as and when they need to. If you pigeon-hole yourself as an "X programmer" you'll limit yourself to relatively uninteresting, interchangeable roles.

Tags: programmers, programming, programming-languages, quora

Which should I learn: Python or PHP?

2013-04-16T16:01:00+00:00

My answer to Which should I learn: Python or PHP? on Quora

Python will teach you more about programming than PHP - and you'll be able to learn PHP easily if you learn Python first.

Tags: php, programming, programming-languages, python, quora

What are some hidden features of Python?

2013-03-25T13:51:00+00:00

My answer to What are some hidden features of Python? on Quora

Generators and Iterators are pretty amazing. These two tutorials will really open your eyes as to how powerful they can be:

Both by David Beazley. To my mind they are the most fascinating Python tutorials out there.

Tags: programming, programming-languages, python, quora

How do I learn Python fast?

2013-01-26T12:55:00+00:00

My answer to How do I learn Python fast? on Quora

Learn how to use the Python interactive prompt and start solving problems with it. The official Python tutorial is an excellent place to start: http://docs.python.org/2/tutorial/

Tags: programming-languages, python, software-engineering, quora

Which language and framework would you use today?

2012-12-25T16:34:00+00:00

My answer to Which language and framework would you use today? on Quora

Unless I had a very good reason to use something else (a pure websocket/real-time collaboration app perhaps) I'd go with stock Django on PostgreSQL and maybe a bit of Redis. Simple, powerful, stable and works reliably.

Tags: frameworks, programming, programming-languages, web-development, quora

How can some really large services (like Dropbox) afford to use Python as a primary language, if it's one to two orders of magnitude slower than other, compiled languages?

2012-12-09T16:52:00+00:00

My answer to How can some really large services (like Dropbox) afford to use Python as a primary language, if it's one to two orders of magnitude slower than other, compiled languages? on Quora

Because raw language speed often doesn't matter that much. In the case if Dropbox the client software spends most of its time waiting for bits to load from the network or from disk. Most large websites spend their time waiting for the database. You can't speed up network or disk performance by using a faster language.

Tags: programming, programming-languages, python, web-development, quora, dropbox