Will Crichton @tonofcrates Twitter profile

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Will Crichton

@tonofcrates

2 years

Latency Numbers Every Programmer Should Know

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Will Crichton

@tonofcrates

3 years

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Will Crichton

@tonofcrates

1 year

This is a REAL string in Rust. This is what they don't want you to see with their "abstractions."

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Will Crichton

@tonofcrates

2 years

I love that Types and Programming Languages has a dependency graph of its chapters, followed by a recommended curriculum as a curated topological sort.

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Will Crichton

@tonofcrates

2 years

If you're learning Rust right now, try out our interactive version of the Rust Book. It has: - Quizzes to help check your understanding - Highlighting to help you keep notes and give feedback - Plus more features on the way!

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Will Crichton

@tonofcrates

2 years

Js: - Compiler: esbuild - Types: tsc - Packages: yarn - Tests: jest - Monorepo: lerna - Build script: node Rust: - Compiler: cargo - Types: cargo - Packages: cargo - Tests: cargo - Monorepo: cargo - Build script: cargo

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Will Crichton

@tonofcrates

1 year

We just added a new chapter on ownership to the Rust Book Experiment. It provides a deeper look into how Rust works at runtime, and why the borrow checker will catch unsafe programs. Check it out:

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Will Crichton

@tonofcrates

3 years

1 year, 1 RFC, and 1k LOC later... it's finally here! Rustdoc can now automatically scrape code examples from your workspace's examples/ directory as documentation for functions. Check out a live demo:

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Will Crichton

@tonofcrates

3 years

PL papers are hard to read, and LaTeX / PDF doesn't make it easier. So I decided to make the LaTeX of the future. You can check out in my HATRA'21 paper: "A New Medium for Communicating Research on Programming Languages"

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Will Crichton

@tonofcrates

2 years

Personal news: I'm starting a postdoc with @ShriramKMurthi ! Our goal is making Rust easier to learn. We'll be designing curricula, visualizations, and IDE tools to help devs understand concepts like ownership and traits. And we are partnering with the inimitable @nikomatsakis .

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Will Crichton

@tonofcrates

1 year

Monday Memory Mystery: guess why these assertions hold in Java. (Note that this behavior is *in the language spec*, not an implementation detail of the JVM.)

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Will Crichton

@tonofcrates

4 months

I wrote some ideas for how to actually make HTML documents a viable replacement for PDFs.

Portable EPUBs

A proposal for the next generation of portable documents.

willcrichton.net

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Will Crichton

@tonofcrates

1 year

Level up your Rust skills by turning off the borrow checker!

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Will Crichton

@tonofcrates

2 years

An underappreciated aspect of functional programming is that it's different from other styles because it arose from a historical context where the foremost goal was to formally reason about semantics, not to accomplish programming tasks on existing hardware.

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Will Crichton

@tonofcrates

1 year

Unreasonably excited about some upcoming additions to our Rust Book Experiment!!

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Will Crichton

@tonofcrates

1 month

Guess who's about to become Rhode Island's #1 Rustacean and #2 document engineer (behind Andy van Dam, ofc). Catch me as an assistant prof at Brown CS in 2025!

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Will Crichton

@tonofcrates

2 years

As Rust gets more popular, I think it's important not to lose sight of how much nicer it is to write some programs in languages like OCaml.

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Will Crichton

@tonofcrates

1 year

Relearning that PHP has absolutely psychotic semantics for higher-order functions: function foo() { echo "bar"; } function twice($f) { $f(); $f(); } twice('foo') That's right, you pass the function name **as a string**!

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Will Crichton

@tonofcrates

8 months

Hey I'm on the academic job market. I build systems to make programmers smarter, informed by PL theory (to make correct & generalizable tools) and HCI theory (to make humanly-useful tools). Also, students say I'm "one of the best lecturers at Stanford."

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Will Crichton

@tonofcrates

2 years

Working on tools for thought (keynote slides about cognitive design)

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Will Crichton

@tonofcrates

2 months

Rust trait errors are about to get a lot more... explorable!

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Will Crichton

@tonofcrates

2 years

The Typescript compiler has adopted the famous "monofile" approach to codebase organization:

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Will Crichton

@tonofcrates

1 year

One striking stat from the Rust Book Experiment is that 60% of Rust learners self-report as not proficient in a systems language (C or C++). 95% self-report as not proficient in a pure functional language (OCaml or Haskell).

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Will Crichton

@tonofcrates

1 year

My greatest achievements in the Rust Book Experiment are high-entropy questions. This question has a nearly uniform distribution across all answers:

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Will Crichton

@tonofcrates

3 years

A debugger is not a debugger, it is an interactive program executor. The sooner we internalize this, the sooner we can talk about what should really be considered a “debugger.”

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Will Crichton

@tonofcrates

1 year

(nervously reading a script, glancing at an offscreen presence) The picture above is not a string. A string is a... beautiful abstraction which would never have so many fields. Strings have always looked like this:

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Will Crichton

@tonofcrates

2 years

Mr. Miri & The Small Steppers

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Will Crichton

@tonofcrates

3 years

Flowistry is a set of powerful IDE tools for Rust. It uses techniques from my research to analyze a program's information flow, and visualize the flow in several ways. An alpha release is now available! Works with VSCode and nightly Rust projects.

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Will Crichton

@tonofcrates

3 years

Just realized my shirt matches my syntax highlighting.................

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Will Crichton

@tonofcrates

1 year

"The systems programmer has read the kernel source, to better understand the deep ways of the universe, and the systems programmer has seen the comment in the scheduler that says “DOES THIS WORK LOL,” and the systems programmer has wept instead of LOLed."

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Will Crichton

@tonofcrates

11 months

> open a PL paper > shit it uses category theory > fine it's time to learn > open "Category Theory for PL Dummies" > 800 pages of definitions > at last, motivating applications > "X is actually Y. to see why this connection is useful, read these 5 papers" > mfw

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Will Crichton

@tonofcrates

8 months

New paper w/ @ShriramKMurthi , conditionally accepted to POPL'24: how do document languages compose content and computation? The key mechanism is the *template*, which we model by extending to System F to create the *document calculus*.

A Core Calculus for Documents

Passive documents and active programs now widely comingle. Document languages include Turing-complete programming elements, and programming languages include sophisticated document notations....

arxiv.org

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Will Crichton

@tonofcrates

1 year

@arian4n Check out in a few weeks and you'll see it live!

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Will Crichton

@tonofcrates

3 years

Excited to announce my debut PL/HCI paper appearing at CHI'21: "The Role of Working Memory in Program Tracing". Ever found it hard to remember stuff while you read a program? That's working memory! Check out our experiments exploring this phenomenon.

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Will Crichton

@tonofcrates

9 months

Our OOPSLA'23 paper is now on arXiv. We developed a new pedagogy for teaching Rust's ownership model, and we evaluated the pedagogy's learning outcomes with data from thousands of Rust learners.

A Grounded Conceptual Model for Ownership Types in Rust

Programmers learning Rust struggle to understand ownership types, Rust's core mechanism for ensuring memory safety without garbage collection. This paper describes our attempt to systematically...

arxiv.org

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Will Crichton

@tonofcrates

1 year

Very happy that the tool can now explain the mysterious "hidden type captures lifetime that does not appear in bounds" error.

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Will Crichton

@tonofcrates

1 year

I present to you: the toughest question in the entire Rust Book Experiment. Only 17% of readers get it right!

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Will Crichton

@tonofcrates

4 months

My RustConf 2023 talk is, at last, on YouTube. It summarizes a year of research on systematically making Rust easier to learn.

RustConf 2023 - The Art and Science of Teaching Rust

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www.youtube.com

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Will Crichton

@tonofcrates

2 years

I've noticed a lot of Rust APIs nowadays use "trait sugar" for flexibility, e.g. impl Into<String> instead of String. But a concern for users is how much worse the error messages become. Compare: fn f(s: String) {} fn g(s: impl Into<String>) {} fn main() { f(0); g(0); }

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Will Crichton

@tonofcrates

2 years

When I taught CS 242, I argued PL history can be divided between Turing languages and Church languages. Turing languages were invented with respect to the machines that existed at the time. Church languages were invented usually for formalizing mathematical or logical domains.

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Will Crichton

@tonofcrates

8 months

Some notes on a recent performance optimization adventure. The benchmark is open-source if you want to try and surpass me!

Analyzing Data 180,000x Faster with Rust

How to hash, index, profile, multi-thread, and SIMD your way to incredible speeds.

willcrichton.net

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Will Crichton

@tonofcrates

2 years

Really liking this interaction -- I call it "focus mode". Turns slicing into an ambient interaction. Click anywhere, immediately see the forward and backward slice of what's under your cursor.

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Will Crichton

@tonofcrates

2 years

Try explaining to a Rust newbie why one of these compiles and the other doesn't :'|

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Will Crichton

@tonofcrates

4 years

It's sad that ownership/borrowing is always explained in terms of application to memory management. One day, we'll talk about a static aliasing discipline the same way we talk about types today. Knowing who points to what is fundamental to good system design.

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Will Crichton

@tonofcrates

7 months

I'll be presenting our OOPSLA'23 paper "A Grounded Conceptual Model for Ownership Types in Rust" tomorrow at 11:18am in Room I. Come and hear about a recipe for helping people understand a type system. A preview:

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Will Crichton

@tonofcrates

1 year

The median Rust learner: * Is a professional programmer * Has been programming for 5 years * Knows Javascript and Python

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Will Crichton

@tonofcrates

5 months

New paper out w/ @ShriramKMurthi accepted to OOPSLA'24: a psychometric analysis of programming language learning. We added ~200 quiz questions to a popular book on Rust and collected ~1,000,000 answers from ~60,000 people over 1 year.

Profiling Programming Language Learning

This paper documents a year-long experiment to "profile" the process of learning a programming language: gathering data to understand what makes a language hard to learn, and using that data to...

arxiv.org

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Will Crichton

@tonofcrates

2 years

Big thanks to everyone who attended my thesis defense. If you missed it, here's a recording. I cover important topics like: * Why (human) memory matters when programming * How the Rust borrow checker works * How to make a lemon meringue pie

Stanford CS PhD thesis defense - "Revisiting Program Slicing with...

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www.youtube.com

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Will Crichton

@tonofcrates

5 years

The more I read, the more it seems like everything I know about education and instruction is completely wrong.

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Will Crichton

@tonofcrates

11 months

What should be considered a design pattern in the era of functional languages? I wrote a paper about this question for FUNARCH @ ICFP. Would love to hear your thoughts:

Typed Design Patterns for the Functional Era

This paper explores how design patterns could be revisited in the era of mainstream functional programming languages. I discuss the kinds of knowledge that ought to be represented as functional...

arxiv.org

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Will Crichton

@tonofcrates

2 years

Dissertation is out! "Revisiting Program Slicing with Ownership-based Information Flow". You might like: * A philosophy for combining theories of cognition & PL * A history of cogpsych research on programming * A perspective on how to make slicing useful

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Will Crichton

@tonofcrates

2 years

Get ready for TRPLISQ (The Rust Programming Language In-Situ Quizzes)

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Will Crichton

@tonofcrates

1 year

That means Rust is a lot of peoples' first exposure to *both* systems programming *and* functional programming!

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Will Crichton

@tonofcrates

2 years

I was curious about the landscape of research about Rust, so I put together a Zotero library of 50+ publications from the last 10 years and loosely organized them. For the interested:

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Will Crichton

@tonofcrates

2 years

The first public release of Nota is now available! Installation and tutorial can be found at:

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Will Crichton

@tonofcrates

2 years

Weirdest part about using Typescript is that it has the most complex type system of any major PL today, but you can also just opt out at any time.

Will Crichton

@tonofcrates

2 years

@shwestrick Honestly no idea. TS modules aren't great but are workable enough. But FWIW the TS type system is actually insanely complicated. It variously supports: gradual typing, structural subtyping, dependent typing, type combinators, multiple inheritance through mixins, ...

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Will Crichton

@tonofcrates

8 months

Also, one last brag: I have *impeccable* taste in programming languages. In 2018, I was teaching in my PL course: - OCaml - Rust - WebAssembly - Lean Five years later, I'm running 4/4 in terms of "languages people are excited to use in 2023".

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Will Crichton

@tonofcrates

1 year

We just released Quizicist, an AI tool to generate multiple-choice questions about text content (e.g. a textbook or lecture notes). Try it out:

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Will Crichton

@tonofcrates

2 months

The entire field of PL right now: what if it was dynamically scoped.... but statically typed..............?

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Will Crichton

@tonofcrates

2 years

I am defending my thesis, "Revisiting Program Slicing with Ownership-based Information Flow", next Friday May 6 at 3pm PT. Please attend if you're interested! The talk is designed to be broadly accessible. Gates 174 in-person, or you can watch on Zoom (DM me for the link).

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Will Crichton

@tonofcrates

2 years

I feel like there should be more DSLs (and corresponding theory) for describing patterns. Regular expressions are nice for basic sequences, but what about: * Multiple overlapping sequences * Spatiotemporal data * Trees, DAGs, graphs

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Will Crichton

@tonofcrates

2 years

Nota demo is now live:

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Will Crichton

@tonofcrates

3 years

I'll be live-tweeting my highlights from HOPL IV, the once-in-a-generation conference about the history of programming languages.

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Will Crichton

@tonofcrates

6 years

Is there a version of math with better names for things? Imagine if we had "Naur loop" and "Hoare loop" instead of "for loop" and "while loop." Yet we have Cauchy–Schwarz inequality, Kullback–Leibler divergence, Euler's formula, ...

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Will Crichton

@tonofcrates

1 year

@tekknolagi Not String or &str, but a secret third thing (Vec<u8>)

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Will Crichton

@tonofcrates

25 days

While folks are starting to get excited about GC-ified Rust, just remember -- real ones have been asking since 2016, "what if we just wrapped everything in Rc<RefCell<T>>?"

GitHub - willcrichton/lia: A high-level language for Rust

A high-level language for Rust. Contribute to willcrichton/lia development by creating an account on GitHub.

github.com

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Will Crichton

@tonofcrates

5 months

I would hate it if everyone read my dissertation. I bet you would find soooo many issues if you read it cover-to-cover and grappled with all the ideas. God forbid that people find the convenient link on my website:

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Will Crichton

@tonofcrates

5 years

One striking feature of programming language history is that two of the most influential languages ever created were designed by committee: Algol and Haskell, both under quite similar circumstances.

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Will Crichton

@tonofcrates

2 years

Are there tools that can automatically generate program visualizations like this? That is: generic stack/heap vis + unrolled in time (no stepping).

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Will Crichton

@tonofcrates

9 months

Tearing my PhD diploma off the wall to replace it with this:

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Will Crichton

@tonofcrates

1 year

Dear god.

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Will Crichton

@tonofcrates

3 years

@flyingcroissant @geoffreylitt Imagine every 10,000px-long blogspam website condensed to this:

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Will Crichton

@tonofcrates

21 days

Hah, frontend web devs are so stupid, using an arbitrary assignment of integers to manage z-index conflicts. Time to take a big sip of coffee and see how type theorists deal with overlapping type classes.

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Will Crichton

@tonofcrates

2 years

Devising a demented vocabulary so my students will never be able to use Copilot. Good luck asking for a method that can hedgetrim an N-way pseudo-shrub

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Will Crichton

@tonofcrates

1 year

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Will Crichton

@tonofcrates

2 years

Added some more good ideas to my list. And they can be yours for the low, low price of $0!

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Will Crichton

@tonofcrates

11 months

After a brief trial, this seems like a useful complement to other information sources, but not a real game-changer. Eg I opened the Rust compiler source and asked where I could find diagnostics relating to trait errors, and it hallucinated 5 files that don't exist.

Steve Yegge

@Steve_Yegge

11 months

I'm excited to announce that Cody is here for everyone. Cody can explain, diagnose, and fix your code like an expert, right in your IDE. No code base is too challenging for Cody. It's like having your own personal team of senior engineers. Try it out!

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Will Crichton

@tonofcrates

2 years

This historical perspective falls apart in the last decade. Many new languages (Rust, Swift, Scala, ...) have both Church and Turing influences. I argue in my course that this is because software is getting so complex that primitives designed for reasoning are now essential.

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Will Crichton

@tonofcrates

8 months

go ahead. keep screaming "Performance Has Regressed" at me. it only makes my runtime Worse

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Will Crichton

@tonofcrates

6 years

What is Systems Programming, Really?

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Will Crichton

@tonofcrates

1 month

I would die of shame if I cited a researcher and they proceeded to dunk on me like this.

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Will Crichton

@tonofcrates

3 years

Excited for my upcoming book, "Rust for Clojurists Who Also Know A Bit of Haskell and Took a Systems Programming Class Back in College But It's Been A While"

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Will Crichton

@tonofcrates

1 year

@ShriramKMurthi Q: "How do you make a deep copy of an object [in Java]?" A: "A safe way is to serialize the object, then deserialize. This ensures everything is a brand new reference."

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Will Crichton

@tonofcrates

2 years

The world wants a better document language for the web! If you are an HCI researcher, a tools-for-thought enthusiast, a Javascript nerd -- now is the time to work on this problem. But we need a revolution, which I don't think will come from incremental improvements on Markdown.

Stripe

@stripe

2 years

Today we’re open-sourcing Markdoc, the content-authoring system that powers the Stripe docs. You can now freely build documentation, static pages, or tooling with the same tools we use: . ✍️

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Will Crichton

@tonofcrates

13 days

Giving several talks, most virtually. Come watch! 5/23: LangSec - "Towards Language-Theoretic Security for Dynamic Documents" 5/28: JetBrains TV - "Teaching Rust" 8/22: Topos Institute - "The Human Factors of Type Systems" 10/23: P99 Conf - "The Performance Engineer's Toolkit"

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Will Crichton

@tonofcrates

2 years

ES6 JS is actually a very pleasant language now. But its tools require so much more work than in a centralized ecosystem like Rust. Billions of .config.json files, dozens of interop packages like esbuild-jest or estrella.

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Will Crichton

@tonofcrates

6 years

Sneak peek from my first lecture in CS 242. The world of programming languages is clearly trending towards better type systems!

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Will Crichton

@tonofcrates

28 days

More convinced than ever that the programming stack of the future is Lean Rust Wasm. And Typescript until there's a good Lean→JS compiler.

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Will Crichton

@tonofcrates

2 months

Proof assistants are a great motivator for abstract algebra. "Ugh I don't want to prove all these facts for my new data structure... Oh wait, but if I think of it as a semilattice, I'll get these theorems and tactics for free!"

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Will Crichton

@tonofcrates

2 years

One extension of this idea, from a convo with @neurocy : what if tools could indicate the conceptual dependencies of an object in context? Eg "you must understand closures, traits, and async to use this Rust library."

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Will Crichton

@tonofcrates

1 year

"So of course, this doesn't compile, as you can see he-- wait what?"

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Will Crichton

@tonofcrates

7 months

This Google PM really gets me. The thing I hate the most about conferences is meeting new people, and the solution I'm looking for is to replace myself with an AI.

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Will Crichton

@tonofcrates

2 years

I just published v0.1 of mdbook-quiz, a tool for embedding interactive quizzes into Markdown books. Try it out! Live demo: Docs:

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Will Crichton

@tonofcrates

1 year

@3m00n_ ⭐ for getting the integer size correct!

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Will Crichton

@tonofcrates

3 months

You'll never find definitive proof that I lobbied Joe Biden to federally mandate the use of my research.

Miguel Piedrafita ✨

@m1guelpf

3 months

C is now illegal

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Will Crichton

@tonofcrates

1 year

@sliminality Added support for enums, just for you

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Will Crichton

@tonofcrates

2 years

One day, all knowledge will be embedded into the OmniGraph.

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Will Crichton

@tonofcrates

1 year

I just added ~75 more quiz questions, so now the Rust Book Experiment covers the entire book. Check it out starting here:

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Will Crichton

@tonofcrates

3 years

What if Rosetta Code actually had a good interface? Check out my "expressiveness benchmark" for data analytics DSLs that helps compare implementations of the same task in different languages.

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Will Crichton

@tonofcrates

2 years

Not to mention how many times I've had to google "yarn vs npm", "esbuild vs webpack", "jest vs mocha", "cjs vs esm"...

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