Jimmy Koppel @jimmykoppel Twitter profile | Pikagi

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Jimmy Koppel

@jimmykoppel

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Turning good engineers into great at . Reverse engineer. Blogs about software design at . Ph. D. in programming languages from @MIT .

Cambridge, MA

https://t.co/r6u0DWAkCk

Joined August 2014

Don't wanna be here? Send us removal request.

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@jimmykoppel

Jimmy Koppel

1 year

The world runs on software. When software is hard to change, so is the world They say you can't teach software design. That it has to be learned through hard experience That good programmers are born, not made I say: challenge accepted My magnum opus:

Learn Advanced Software Design

Eliminate impostor syndrome, Escape software influencer dogma, Rise above subjective debates, Give concrete answers you can explain. Unleash your full potential as a software engineer

self-service.mirdin.com

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@jimmykoppel

Jimmy Koppel

5 years

Programmer: "If someone types a letter at the beginning of a sentence, they probably want it capitalized." Result: Powerpoint just tried to correct λ-calculus to Λ-calculus.

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@jimmykoppel

Jimmy Koppel

9 months

What makes good API documentation? To answer this, we must ask: what do programmers need to know to use an API? One paper claims there are three major parts Enter "A Theory of Robust API Knowledge" by Kyle Thayer, @sarahchasins , and @amyjko . 🧵

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@jimmykoppel

Jimmy Koppel

7 months

Hyrum's Law: With a sufficient number of users of an API, it does not matter what you promise in the contract: all observable behaviors of your system will be depended on by somebody. Solution: Destroy observable behaviors

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@jimmykoppel

Jimmy Koppel

9 months

Programming tip: Memorize your standard libraries Make flashcards for the standard functions. If you don't use spaced repetition, then start. I did this for Haskell years ago. It brought me from constantly looking at documentation to coding at the speed of thought

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@jimmykoppel

Jimmy Koppel

2 years

Physical copy finally arrived.

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@jimmykoppel

Jimmy Koppel

10 months

@JessicaHullman On my way to Singapore in 2019, I read a 10-year old paper by @ilyasergey , and then asked about an error I found early on when we met Why? It was directly related to the work I presented Turns out, I'm allowed to be interested in things others were a long time ago

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@jimmykoppel

Jimmy Koppel

5 years

Me earlier this year: everything we do is just defunctionalization. Me last month: everything I did 4 years ago was also just defunctionalization. Just released: my guest post for the @sigplan blog (ed. @michael_w_hicks ), giving a full 7 applications.

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Defunctionalization: Everybody Does It, Nobody Talks About It

An impressive number of transformations in both compilers and in ordinary programming are special cases of a transformation called “defunctionalization.” This post explains what it is a…

blog.sigplan.org

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@jimmykoppel

Jimmy Koppel

2 years

1/ Had a blast Monday giving a code-review guest lecture for MIT's 6.1040 "Software Studio" class with Daniel Jackson. Now my head's full of examples of good and bad frontend code. n^2 likes = n+1 examples of making cleaner and more robust frontend code First one's free.

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@jimmykoppel

Jimmy Koppel

4 years

4 years, 4 papers, and way too much fiddling with CSS later, I am pleased to finally release my Cubix "One Tool, Many Languages" framework to the world. May the days of single-language tools soon be behind us.

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@jimmykoppel

Jimmy Koppel

1 year

In 2019, I brought you defunctionalization, the "Best Refactoring You've Never Heard Of" In 2023, enter: The best multicore-parallelization refactoring you've never heard of

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@jimmykoppel

Jimmy Koppel

7 months

Every time I hear someone advocate for teaching "practical" languages in universities, I recall the words of Mary Shaw, who helped create the field of software architecture. Had she succumbed, people would have learned JCL instead of algorithms. Don't know what JCL is? Exactly

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@jimmykoppel

Jimmy Koppel

9 months

ESR says: Learn Lisp. Even if you never use it, the profound enlightenment makes it worth it. What’s today’s equivalent? I think it’s Haskell. Lisp is like learning a few extra tricks beyond what you already know. Haskell is like learning to program all over again.

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@jimmykoppel

Jimmy Koppel

8 months

Yesterday we lost the 1984 Turing laureate, but no-one's talking about his deepest contribution: stepwise refinement In 1971, he showed how to turn pseudocode into real code. 50 years later, refinement-based synthesis is being used to generate cryptography code in Chrome RIP

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@jimmykoppel

Jimmy Koppel

3 years

It's true; I'm Dr. Koppel now

@Ngnghm

💻🐴Ngnghm

3 years

Congratulations to newly Doctor @JimmyKoppel for his work on meta-meta-programming!

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@jimmykoppel

Jimmy Koppel

2 years

Hyrum’s Law applies, even when you take into account Hyrum’s Law. Go's map iteration order is random to prevent dependence on its order. Then someone made a load balancer depend on its randomness. But it wasn't random enough.

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@jimmykoppel

Jimmy Koppel

8 months

So you think "functional" and "imperative" languages are a thing? Bet you can't figure out what language this is

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@jimmykoppel

Jimmy Koppel

1 year

Language features by gap between invention and penetration in the mainstream languages Algebraic data types: 40 years Lambdas: 80 years Existential quantifiers: 127 years and counting Infinity: It'll be a while

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@jimmykoppel

Jimmy Koppel

5 years

@hillelogram "Write simple code" is a classic case of citrus advice: The only "serious" attempt I've seen to define complexity for a programming-related thing is (Defn. 2). Other approaches are stymied by focusing on code rather than logic.

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@jimmykoppel

Jimmy Koppel

2 years

Theo may have worked hard on this video, but it is dangerously wrong. The video is based on a couple of deep misconceptions, and can actively make your code harder to change. The short explanation is "principal typing is not modular." What does that mean? Time for a 🧵

@t3dotgg

Theo - t3.gg

2 years

The Case Against Return Types, new video up now

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@jimmykoppel

Jimmy Koppel

5 years

The two best-known codebases I've worked in are Postgres and Android ART. Postgres had this; ART did not. I learned Postgres's internals several times faster.

@hillelogram

Inactive; Bluesky is @hillelwayne(dot)com

5 years

More codebases need developer walkthroughs that explain how the codebase does X. "The TimeFarbler UI is in foo/bar, which pulls config from baz/blat. Most of the timefarble implementation is auditing; the actual mutation happens in the timefarble -> x -> y -> z call stack."

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@jimmykoppel

Jimmy Koppel

11 months

I used to think category theory concepts like free objects were useless Then I found Craigslist Now, I use free objects every day

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@jimmykoppel

Jimmy Koppel

8 months

Sometimes I ask someone to learn something, and they just regurgitate the textbook. They don't realize that's not understanding My trick: Bloom's taxonomy They rate themselves, and realize they need to get to a higher level And hopefully get cured of bad study habits forever

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@jimmykoppel

Jimmy Koppel

11 months

MYTH: Bad software design rarely causes business failures FACT: Software design mistakes regular cause massive damage Recent example: Toyota blames "recent maintenance," but a single overflowing disk should not shut down 14 factories

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@jimmykoppel

Jimmy Koppel

4 years

1/ Last week, I went through “Designing Systems Programs” (1970), quite possible the world’s oldest software engineering book. I've read many software writings rom the 70's that feel refreshingly modern and deeply insightful, even 40 years later. But this is an alien text.

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@jimmykoppel

Jimmy Koppel

7 months

"FP languages" is a misnomer There is only functional style. Is OCaml a functional language? I know a professor who treats it as "C with types" and likes replacing list maps with for-loops Is JavaScript a functional language? "SICP for JS" treats it as a skin on Scheme.

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@jimmykoppel

Jimmy Koppel

5 years

"There are two things to know about TLA+. The first is that it checks models, not code. The second is that its syntax makes no sense." I've posted my review of @hillelogram 's book, Practical TLA+:

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@jimmykoppel

Jimmy Koppel

5 years

Three months ago, I asked Mike to coteach my Reverse Engineering Course. Two months ago, he invited me to reverse-engineer a voting app with him. One month ago, we had some frightening results, and began disclosure. Thank you @nytimes ; we're proud to share our work today.

@mspecter

Michael A. Specter 👻

5 years

Today, myself and co-authors @jimmykoppel and @djweitzner released a paper discussing a slew of vulnerabilities we found in @voatz , a blockchain voting app that's been used in US federal elections. You can read about it in the @nytimes !

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@jimmykoppel

Jimmy Koppel

1 year

The one true way to hide your E-mail address

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@jimmykoppel

Jimmy Koppel

9 months

Every programmer should learn the HS Traversable library The easiest code to read has everything in 3 lines The second easiest lets you glance at it and instantly see 3 chunks That’s what understanding traversals gives you. Even if you don’t use it, it will stretch your brain

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@jimmykoppel

Jimmy Koppel

3 years

Today’s software design example: Memcache::set(…, expire=60*60*24*29) makes a key expire in 29 days Memcache::set(…, expire=60*60*24*30)? 30 days Memcache::set(…, expire=60*60*24*31)? Expires on February 1, 1970 (i.e.: instantly) h/t @edmondlau

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PHP: Hypertext Preprocessor

PHP is a popular general-purpose scripting language that powers everything from your blog to the most popular websites in the world.

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@jimmykoppel

Jimmy Koppel

9 months

Saying companies never die of tech debt is like saying people never die of old age It’s always ‘Lost too many sales to competitors" “Couldn’t pivot fast enough” But if they could produce 2x the features with half the bugs, maybe they'd have survived Good software engineering

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@jimmykoppel

Jimmy Koppel

3 years

I've trained about 200 engineers, but there's a lot of bad software out there demanding more good people. It's going to take some serious tech to scale up. Thank you to @slatestarcodex for this support, and to @AndrewOlney1 and @XiangenHu for helping me enter the field of ITS.

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Jimmy Koppel

9 months

Each time this Tweet crosses n^2 likes, I shall command ChatGPT to make the code higher "quality"

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@jimmykoppel

Jimmy Koppel

3 years

"DRY" is a great example of an idea perverted by poor choice of name. The original presentation in The Pragmatic Programmer defined it basically as "single point of truth," but people assume it means "no syntactic clones."

@Killectro

DJ Mitchell ✊🌹

3 years

@nicklockwood @jimmykoppel phrases it slightly differently as avoiding repetition of *concepts* rather than code, which I really like. I love this episode of @corecursive with him and recommend it to basically everyone.

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@jimmykoppel

Jimmy Koppel

2 years

Just because you can give your callers more information doesn't mean you should. Just because you can let them do more doesn't mean it's good. For the power of a design lies not in what it can do, but in what it can't do.

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@jimmykoppel

Jimmy Koppel

1 year

Others are saying that dynamic/static and weak/strong is a false dichotomy. But it goes further. The way most programmers are taught categories of PLs is broken. Think features, not families. Imperative is a feature, not a language. Pure is the default. Genetics, not taxonomy

@john_chandler

John Chandler 🔶️🔰

1 year

If there's programming language topic that really needs to be taught, it's the difference between static/dynamic typing and strong/weak typing. I've even had comp sci lecturers get the two confused, saying a language is weakly typed when what they mean is *dynamically* typed.

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@jimmykoppel

Jimmy Koppel

1 year

All code should be written with 1. The assumption it will never be replaced (because they cost isn't worth it) 2. The assumption it will be replaced in a year

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@jimmykoppel

Jimmy Koppel

1 year

One of the most important skills a developer can cultivate is understanding the knowledge and reasoning they are using to create code. Matt here is doing a fine job of showing the "why"

@_swanson

matt swanson 😈

1 year

25 year old me: don't write code comments, just use clear naming 35 year old me:

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@jimmykoppel

Jimmy Koppel

4 years

"Some programmers hardcoded the size of this thing was 4 bytes. Now I need to change them all." 2 hours of grep later: "K, found them all" Testing: breaks, because you still missed some Want that to stop? Come learn about our new Yogo tool at PLDI 2020:

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Teaser video: "Semantic Code Search via Equational Reasoning"

www.youtube.com

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@jimmykoppel

Jimmy Koppel

1 year

@dmokafa @dmokafa What test would you write for this? And how is it not verified?

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@jimmykoppel

Jimmy Koppel

2 years

Like it or not, the growth of JavaScript is unstoppable. It is now more than 50% of code on GitHub. It has evolved to fill every niche in the ecosystem. It is too fit This can only mean one thing: Humanity is no longer the dominant species.

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@jimmykoppel

Jimmy Koppel

5 years

(1/3) This is a boarding pass. Why is there no space before his middle name? It's because the name goes through a software system based on SABRE, which doesn't support middle names, and has a tight character limit. Why? Way back when, IBM used to charge airlines per byte.

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@jimmykoppel

Jimmy Koppel

7 months

@orderwithchaos Hyrum's law explicitly says that writing the contract isn't enough.

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@jimmykoppel

Jimmy Koppel

11 months

Saying companies never die of tech debt is like saying people never die of aging

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@jimmykoppel

Jimmy Koppel

7 months

Among the worst advice about training is "The only way to get better at X is to just do X" My last semester of college was spending 10 hours a week training for the ACM-ICPC World Finals. Twice a week, we'd race to code up algorithm problems faster than a recording of the

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@jimmykoppel

Jimmy Koppel

2 years

A Google engineer goes up for promotion. He is denied. Next year, he writes a design document about a feature he just launched, taking great pains to exaggerate how complex it is. The "simplifications" of how it actually works go in the appendix. He gets promoted. #truestory

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@jimmykoppel

Jimmy Koppel

1 year

When I started training professional devs, I found I was among the onyl people doing advanced tech-agnostic software engineering training. 7 years and 4 days later, I still enjoy a near-monopoly. 300 students and counting have gone through Mirdin's training.

@benawad

Ben Awad

1 year

The coding tutorial space looks super crowded, but it is actually a barren wasteland after the basics of a programming language everyone is making -> "Learn Python" some -> "API Auth in Python" or "DBs + Python" few -> "How to build a full project in Python"

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@jimmykoppel

Jimmy Koppel

10 months

These two lines carry deep software design wisdom It lets me keep output and logs distinguished Keeps the logging-centric code organized But without creating a separate logging. py Without figuring out an actual logging setup I've saved the intention, but deferred the work

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@jimmykoppel

Jimmy Koppel

9 months

Every once in a while you learn something that makes you look back and think “That’s what I was doing wrong” This book did that for me: When I Say No, I Feel Guilty I’d been reliving so many times when someone said hurtful stuff or manipulated me With this book: finally healed

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@jimmykoppel

Jimmy Koppel

2 years

A GHC plugin that turns types into Haskell code? Automatically generating property-based tests? Both easy-peasy, thanks to ECTAs, a new kind of constraint solver we invented. Come hear me and @tritlo talk about our recent work with @polikarn and @ZhengGuo069 .

@HaskelInterlude

The Haskell Interlude

@HaskelInterlude

2 years

In our new episode @jimmykoppel and @tritlo chat with @wouterswierstra and @nikivazou , enjoy!

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@jimmykoppel

Jimmy Koppel

8 months

To level up as a software engineer, practice regularly Ask yourself: What have I done lately that's like playing scales? Lots of ways to do so. Opportunities abound. A new one from @jeremyphoward : when you see a function with lots of optional arguments, practice using each

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@jimmykoppel

Jimmy Koppel

3 years

If you're a software engineer, is studying theory a path to productive enlightenment, or a giant time sink? Answer: Yes. New blog post: Why Programmer's Should(n't) Learn Theory

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@jimmykoppel

Jimmy Koppel

4 years

With books like @opticsbyexample coming up, lots of people want to rework old code to use lenses. Watching a headset designer writing a project proposal last night as she accidentally coined the term for this: refractoring.

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@jimmykoppel

Jimmy Koppel

2 years

Get the fork() out of my kernel! A great essay on why it's bad: And the more general principles behind it:

@Jonathan_Blow

Jonathan Blow

2 years

fork() has to go down in history as one of those ideas, like the C switch statement, that seemed cool initially but turned out to be one of the worst ideas ever. It causes so many problems, I am astounded that in 2023 it is still the standard (and only?) thing on Linux.

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@jimmykoppel

Jimmy Koppel

9 months

Stop wasting time tracking down where things come from! Put the function name in every error message Put a date on every note in the codebase

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@jimmykoppel

Jimmy Koppel

3 years

It is my pleasure to announce that I am now a Scientific Advisor to @KuraTechAR . Kura is playing software design on hard mode, wanting to have software that will run decades from now on dozens of custom variants of their headset. I am honored to help them create the AR future.

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@jimmykoppel

Jimmy Koppel

9 months

People ask me about OO vs. functional programming. But that’s the wrong question. C++ has lambdas. Java has monads. Python programmers use map instead of loops FP already won. We are all functional programmers now.

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@jimmykoppel

Jimmy Koppel

7 months

Wouldn't it be nice if debuggers presented information the way you think about it? After 5 years, we finally have an intro JS debugger that renders closures as diagrams. What will programming look like when your debugger looks like this for apps and distributed systems too?

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@jimmykoppel

Jimmy Koppel

5 years

"The Best Refactoring You've Never Heard Of," now a blog post:

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@jimmykoppel

Jimmy Koppel

5 years

"The Best Refactoring You've Never Heard Of," already up: . Thanks @composeconf organizers for being impressively on-top of A/V.

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The Best Refactoring You’ve Never Heard Of

Compose NYC 2019Speaker: James KoppelEvery problem can be solved by many designs. Often the relation between two designs is that one is a transformation of a...

www.youtube.com

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@jimmykoppel

Jimmy Koppel

2 years

"Man, these scoring rules are really complicated." "I wonder if it's NP-hard." 4 years later, we've proven it. Presenting my paper with @YunWilliamYu , "Skiing is Easy, Gymnastics is Hard: Complexity of Routine Construction in Olympic Sports", in FUN '22.

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@jimmykoppel

Jimmy Koppel

7 months

"Do you teach architecture?" Bro, here''s what architecture can mean in SE * Module-level patterns like Active Record * Stuff between modules * Stuff between whole systems * What database you use * Anything involving diagrams * Anything "high level" whatsoever So.....yes?

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@jimmykoppel

Jimmy Koppel

3 years

@hillelogram I recommend for understanding the Prolog execution model. f(X, Y) has two different meanings depending on mode. Also, Curry report: I do research on multi-language tools. C and OCaml? Child's play. OCaml and Prolog? Terrifying.

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@jimmykoppel

Jimmy Koppel

9 months

Are you using spaced repetition for all your technical knowledge? On a hike last month, I taught my cofounder 1/3 of a DB course I studied this stuff 8 years ago, put it into Anki, and have scarcely looked at it since Imagine if you could do that for everything you’ve learned

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@jimmykoppel

Jimmy Koppel

5 years

A Y2K programmer wishes to sleep through the chaos, and gets cryogenically frozen for a few months. Alas, the vat isn't Y2K compliant, so he's not woken for 8000 years. "Why now?" "You see, the year 10,000 is just around the corner, and your resume says you know COBOL..."

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Jimmy Koppel

2 years

TIL: Some engineers will fight you if you say we should write a spec before doing the work. But if you tell them that we should write down the properties we want our tests to check, they will agree instantly!

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@jimmykoppel

Jimmy Koppel

2 years

Today in data modeling is hard. struct MenuItem { Food food; BOOL withChips; } Time to learn about sum types.

@NoContextBrits

No Context Brits

@NoContextBrits

2 years

I’ll have some chips without chips please mate.

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@jimmykoppel

Jimmy Koppel

4 years

The world runs on software. Those who want to change the world should care about software being easy to change. Latest news: changing genetics is easier than changing Excel. h/t @w_gottschalk

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@jimmykoppel

Jimmy Koppel

9 months

When “good advice” stops working In 1747, Lind proved lemons cure scurvy Then they replaced the lemons with limes. Scurvy came back If you don’t understand why it works, one day it won’t So much SE advice is like this. I call it “citrus advice” We need to find the root cause

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@jimmykoppel

Jimmy Koppel

9 months

Small Haskell trick I just discovered: Problem: I have a GADT, e.g. `Graph v e` whose contents I want to keep opaque, but it contains some instances on v and e I want to expose Solution: pattern GetInstances <- Graph _ E.g.: myGraphOperation g @Graph .GetInstances = ...

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@jimmykoppel

Jimmy Koppel

8 months

"I've read it 5 times, and I still don't understand it" I don't know who needs to hear this, but Rereading doesn't work It feels easier the second time because it's more familiar. Not because you understand it Find another source, ask ChatGPT — do anything else instead.

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@jimmykoppel

Jimmy Koppel

4 years

1/ I want to tell the story of how I came up with thermometer continuations ("Capturing the Future by Replaying the Pasts," , )

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@jimmykoppel

Jimmy Koppel

2 years

I've been on a mission to rigorously define the major terms of software engineering. Abstraction was figured out in the 70's ( ). Daniel Jackson and I figured out dependence 2 years ago. Now made accessible. New post!

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@jimmykoppel

Jimmy Koppel

7 months

A good software designer can write good code in any PL I barely knew Typescript when I did this critique. But I knew that hardcoded list was bad, so I found a language feature that let me fix it General principles made me a skilled language-wielder, not the other way around

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@jimmykoppel

Jimmy Koppel

9 months

Base on their analysis of the literature and their past teaching and research experience, the researchers proposed a theory that API knowledge consists of three factors: Domain concepts, Execution Facts, and API usage patterns

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@jimmykoppel

Jimmy Koppel

3 years

@hillelogram I think this is very true. FP and OOP are not real separate disciplines. FP is a style with lots of higher-order functions; OOP is some mix of a certain namespace-y syntax and using "recursive existential types" (aka "objects"). LP is a totally different execution model.

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@jimmykoppel

Jimmy Koppel

2 years

10n^2 likes = n crazy debugging stories. Like this one, my second craziest.

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@jimmykoppel

Jimmy Koppel

7 months

What's the scariest kind of software to work on? For me, that might be MTG Online, or Dominion. Countless cards, each of which can change the rules and interact. Even a simple version stumps my best students But I see PyDominion has reached full generality.

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@jimmykoppel

Jimmy Koppel

2 years

People think comments and specifications are useless. If you think this, you'll write useless comments and specifications.

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@jimmykoppel

Jimmy Koppel

5 years

Java classes are a combination of: * Namespaces * Modules * Objects * Classes * Object types * Structures/products * Sums * Interfaces (abstract classes) Did I miss any? Each of these concepts has their own type theory, sometimes opposed to each other.

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@jimmykoppel

Jimmy Koppel

5 years

Every time I've heard someone give an example of why early abstraction is bad, my response has been "That's not abstraction." Abstraction is about information hiding, not finding patterns. Finding patterns is called "anti-unification." And anti-unification is not abstraction.

@ericelliott_

Eric Elliott

5 years

Don't abstract too early. Wait until you've copied and pasted a couple times. You need example use-cases to create good abstractions.

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@jimmykoppel

Jimmy Koppel

5 years

Very disappointed by @paulg 's Bel: 10 years after the mistakes of Arc, the new language still claims abstraction while lacking abstract datatypes . I speak as someone who once idolized PG and contributed to the Arc libraries. Excellent review by dfranke:

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@jimmykoppel

Jimmy Koppel

8 months

This thread contains all my refactoring challenges and their solutions #1

@jimmykoppel

Jimmy Koppel

9 months

Refactoring challenge #1 Starting off with a classic It's checking the URL format twice. And it feels fragile; too easy to forget an isValid check. Can you improve this?

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@jimmykoppel

Jimmy Koppel

5 years

“The architectural information typically does not exist in the codebase given our languages today” -- @simonbrown Simon Brown echoing the insights I shared in , in the best talk I've seen in a long time:

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🚀 The Art of Visualising Software Architecture (Simon Brown)

❗️ATTENTION ❗️Registration to DevTernity is running:👉 https://devternity.comAsk somebody in the building industry to visually communicate the architecture o...

www.youtube.com

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@jimmykoppel

Jimmy Koppel

7 months

Why is it that working with marketing feels frantic, and working with BigCo feels lumbering? It's because of a mismatch in Buxton index, a differing time period over which decisions are made Easily the most profound thing I've learned from @swizec Teller.

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@jimmykoppel

Jimmy Koppel

2 years

ChatGPT settles an age-old debate

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@jimmykoppel

Jimmy Koppel

6 years

ALL(*) is a huge achievement in parsing technology, but not many know how it works. Pleased to do my part in changing that.

@the_antlr_guy

Terence Parr

6 years

Check out this great summary of ALL(*) parsing at an MIT programming language lunch lecture by @jimmykoppel ; @samharwell and I designed ALL(*) as part of ANTLR 4. Video: Paper: (w/Kathleen Fisher)

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@jimmykoppel

Jimmy Koppel

8 months

I just watched the incredible documentary "Antarctica: A Year on Ice" by @Antzkiwi . And then I realized: Here are 12 ways maintaining a legacy software system is like wintering at an Antarctic base:

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@jimmykoppel

Jimmy Koppel

7 months

Today I watched my computer struggle with DNS limitations from 1983 while running on an ISA from the 70s. And so I think back to one of my all-time favorite SE quotes: Software is like clay. Soft initially, but then it hardens. It needs to be like gold, malleable for life

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@jimmykoppel

Jimmy Koppel

8 months

This New Year, take some small steps to tidy your code That's the theme of Kent Beck's "Tidy First" It prescribes 16 "tidyings" you can do right now to clean up your code. I'll post one daily The first: Use early returns to flatten guard clauses "Only one return" is so 1985

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@jimmykoppel

Jimmy Koppel

9 months

Micro software design lesson: Found this in a README: code --install-extension my-vscode-plugin-0.0.1.vsix This is Hidden coupling. With this, the README must be updated on every version bump: Instead try code --install-extension my-vscode-plugin-*.vsix Fire and forget

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@jimmykoppel

Jimmy Koppel

3 years

Latest newsletter: Why not to study design patterns

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@jimmykoppel

Jimmy Koppel

11 months

PG in 2006: "nah no-one's heard of that Paypal CEO"

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@jimmykoppel

Jimmy Koppel

3 years

Latest blog post: "Developer tools can be magic. Instead, they collect dust." (Currently #2 on HN, #1 on lobst.ers )

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@jimmykoppel

Jimmy Koppel

3 years

For program synthesis, @rossetate & @mwillsey showed the power of e-graphs @tessalau , @SumitGulwani & @Skiminok , the power of VSAs. @xwangsd , tree automata After studying each, it's obvious all are actually tree automata But someone had to prove it

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Version Space Algebras are Acyclic Tree Automata

Version space algebras are ways of representing spaces of programs which can be combined using union, intersection, and cross-product/``join" operators. In their reified form as ASTs with explicit...

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@jimmykoppel

Jimmy Koppel

6 years

Hyrum’s law: With a sufficient number of users of an API, it does not matter what you promise in the contract: all observable behaviors of your system will be depended on by somebody. Solution: Destroy observable behaviors

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@jimmykoppel

Jimmy Koppel

8 months

@clintonmead Correct! It's from @mmirman 's Imperative Haskell library.

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@jimmykoppel

Jimmy Koppel

7 months

Many programmers can recognize why this code is bad, but 0.01% can articulate why Introducing "path-sensitive code"

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@jimmykoppel

Jimmy Koppel

9 months

The year is 2025. Programmers own chatbots like racehorses, carefully managing their training so they can bring in prizes. Resumes focus on the accomplishments of the chatbot. That means: It will finally be possible to have 10 years of experience in last month's framework.

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