The Peterman Pod

Anders Hejlsberg is the creator of TypeScript and C#, and I asked him about how the TypeScript compiler got 10x faster through a rewrite in Go and his thoughts on how AI has impacted software engineering.

• My ergonomic keyboard project I mentioned, you can follow along here: https://read.compose.llc/
• The Kickstarter page for it: https://www.kickstarter.com/projects/ryanlpeterman/compose-simple-ergonomics-beautifully-done

Podcast links:

• YouTube: https://www.youtube.com/watch?v=cywK3XYYJ2o
• Apple: https://podcasts.apple.com/us/podcast/the-peterman-pod/id1777363835
• Transcript: https://www.developing.dev/p/creator-of-typescript-10x-faster

Thank you to this episode's sponsors for supporting my work:

• WorkOS: makes your app Enterprise Ready with easy to use APIs to add SSO, SCIM, RBAC, and more in just a few lines of code, check them out at https://workos.com/
• Jira by Atlassian: Get more work done with your favorite agents and models all in one place, check them out at https://jira.dev/

Timestamps:

(00:00) Intro
(00:48) Why write a compiler in JavaScript
(07:29) Why rewrite the compiler in Go
(14:49) LLMs for large migrations
(20:12) Why Javascript is so popular
(26:32) Why ever use Javascript on the backend
(32:59) What it takes to build a programming language
(37:06) Will there be fewer languages in 10 years
(42:57) Hands on engineering vs delegation
(49:14) Why fast tooling matters more now
(51:16) AI software engineering predictions
(58:52) The most technically challenging work
(01:02:04) Top book recommendation
(01:03:50) Advice for his younger self
(01:05:00) Outro

Where to find Anders:

• GitHub: https://github.com/ahejlsberg
• X/Twitter: https://x.com/ahejlsberg
• Wikipedia: https://en.wikipedia.org/wiki/Anders_Hejlsberg
• LinkedIn: https://www.linkedin.com/in/ahejlsberg/

Where to find Ryan:

• Newsletter: https://www.developing.dev/
• X/Twitter: https://x.com/ryanlpeterman
• LinkedIn: https://www.linkedin.com/in/ryanlpeterman/
• Threads: https://www.threads.com/@ryanlpeterman
• Instagram: https://www.instagram.com/ryanlpeterman
• TikTok: https://www.tiktok.com/@ryanlpeterman

Referenced in this episode:

• Flow type checker repository: https://github.com/facebook/flow
• TypeScript compiler repository: https://github.com/microsoft/TypeScript
• Algorithms + Data Structures = Programs (book): https://en.wikipedia.org/wiki/Algorithms_%2B_Data_Structures_%3D_Programs
• TypeScript native rewrite: https://devblogs.microsoft.com/typescript/announcing-typescript-7-0/

Leonardo de Moura is the creator of Lean and the Z3 theorem prover. I talked with him about how Lean works and why LLMs plus Lean will fundamentally change how we write software and do math.

• My ergonomic keyboard project I mentioned, you can follow along here: https://read.compose.llc/
• The Kickstarter page for it: https://www.kickstarter.com/projects/ryanlpeterman/compose-simple-ergonomics-beautifully-done

Podcast links:

• YouTube: https://youtu.be/KzdYKeAqWhY
• Apple: https://podcasts.apple.com/us/podcast/the-peterman-pod/id1777363835
• Transcript: https://www.developing.dev/p/creator-of-lean-the-end-of-handwritten

Thank you to this episode's sponsor for supporting my work:

• WorkOS: makes your app Enterprise Ready with easy to use APIs to add SSO, SCIM, RBAC, and more in just a few lines of code, check them out at https://workos.com/

Timestamps:

(00:00) Intro
(00:28) How formal verification works
(05:21) A new way of writing software
(13:15) Proof assistants vs programming languages
(21:06) How Lean has assisted in mathematical breakthroughs
(32:03) When is it worth formalizing software
(33:29) How Lean will impact handwritten math
(38:55) The Z3 theorem prover project he started
(45:44) The most technically challenging work of his career
(51:10) Lean vs its competitors
(01:00:37) The future of Lean
(01:04:10) Technical book recommendations
(01:06:15) Advice for his younger self
(01:07:10) Outro

Where to find Leonardo:

• Wikipedia: https://en.wikipedia.org/wiki/Leonardo_de_Moura
• Website: https://leodemoura.github.io/
• GitHub: https://github.com/leodemoura
• LinkedIn: https://www.linkedin.com/in/leonardo-de-moura-26a27b5/
• X/Twitter: https://x.com/Leonard41111588

Where to find Ryan:

• Newsletter: https://www.developing.dev/
• X/Twitter: https://x.com/ryanlpeterman
• LinkedIn: https://www.linkedin.com/in/ryanlpeterman/
• Threads: https://www.threads.com/@ryanlpeterman
• Instagram: https://www.instagram.com/ryanlpeterman
• TikTok: https://www.tiktok.com/@ryanlpeterman

Referenced in this episode:

• Lean 4: https://github.com/leanprover/lean4
• Mathlib: Lean Mathematical Library: https://github.com/leanprover-community/mathlib4
• Lean4Lean: https://github.com/digama0/lean4lean
• Liquid Tensor Experiment: https://xenaproject.wordpress.com/2020/12/05/liquid-tensor-experiment/
• Veil protocol verification language: https://veil.dev/
• Z3 theorem prover: https://github.com/Z3Prover/z3
• seL4 formally verified microkernel: https://github.com/seL4/seL4

Roberto Ierusalimschy is the creator of the Lua programming language. I interviewed him about Lua's unique strengths, programming language design and predictions for how AI will impact programming languages.

• My ergonomic keyboard project I mentioned, you can follow along here: https://read.compose.llc/
• The Kickstarter page for it: https://www.kickstarter.com/projects/ryanlpeterman/compose-simple-ergonomics-beautifully-done

Podcast links:

• YouTube: https://youtu.be/jCZnFKk6M9A
• Apple: https://podcasts.apple.com/us/podcast/the-peterman-pod/id1777363835
• Transcript: https://www.developing.dev/p/creator-of-lua-scripting-programming

Thank you to this episode's sponsor for supporting my work:

• WorkOS: makes your app Enterprise Ready with easy to use APIs to add SSO, SCIM, RBAC, and more in just a few lines of code, check them out at https://workos.com/

Timestamps:

(00:00) Intro
(00:43) What sets Lua apart
(08:35) Comparing Lua with Python
(13:04) Top book recommendation on language design
(14:20) How JIT works and why it is hard
(23:21) Compiling Python and interpreting C
(30:31) How cross language calls work
(36:58) Lua unique design decisions
(51:17) Predictions for AIs impact on languages
(01:00:10) Top 3 languages to learn to become a better engineer
(01:03:21) Advice for his younger self
(01:04:19) Outro

Where to find Roberto:

• Website: https://www.inf.puc-rio.br/~roberto/
• Wikipedia: https://en.wikipedia.org/wiki/Roberto_Ierusalimschy

Where to find Ryan:

• Newsletter: https://www.developing.dev/
• X/Twitter: https://x.com/ryanlpeterman
• LinkedIn: https://www.linkedin.com/in/ryanlpeterman/
• Threads: https://www.threads.com/@ryanlpeterman
• Instagram: https://www.instagram.com/ryanlpeterman
• TikTok: https://www.tiktok.com/@ryanlpeterman

Referenced in this episode:

• The Evolution of Lua: https://www.lua.org/doc/hopl.pdf
• LuaJIT: https://luajit.org/
• How much does it cost: https://www.youtube.com/watch?v=EUvgoxBm7uc
• JavaScript: The Good Parts (not an affiliate link): https://www.amazon.com/dp/0596517742

Judea Pearl is a Turing Award winner and a pioneer in artificial intelligence and causal reasoning. We talked about how he got into science, his major breakthroughs and his predictions for AI today.

• My ergonomic keyboard project I mentioned, you can follow along here: https://read.compose.llc/
• The Kickstarter page for it: https://www.kickstarter.com/projects/ryanlpeterman/compose-simple-ergonomics-beautifully-done

Podcast links:

• YouTube: https://youtu.be/FleTXB1fAcQ
• Apple: https://podcasts.apple.com/us/podcast/the-peterman-pod/id1777363835
• Transcript: https://www.developing.dev/p/turing-award-winner-early-ai-llm

Thank you to this episode's sponsor for supporting my work:

• WorkOS: makes your app Enterprise Ready with easy to use APIs to add SSO, SCIM, RBAC, and more in just a few lines of code, check them out at https://workos.com/

Timestamps:

(00:00) Intro
(00:54) How he got into AI
(11:17) Greatest scientist of all time
(20:15) What people thought of AI in the 80s
(26:23) Entering academia and researching AI
(34:52) The invention of Bayesian networks
(46:28) Pioneering work in causality
(55:38) The causal hierarchy
(59:34) LLMs and predictions
(01:20:12) A restless mind pays
(01:24:36) Advice for his younger self
(01:26:37) Outro

Where to find Judea:

• X/Twitter: https://twitter.com/yudapearl
• Website: https://bayes.cs.ucla.edu/jp_home.html
• Wikipedia: https://en.wikipedia.org/wiki/Judea_Pearl

Where to find Ryan:

• Newsletter: https://www.developing.dev/
• X/Twitter: https://x.com/ryanlpeterman
• LinkedIn: https://www.linkedin.com/in/ryanlpeterman/
• Threads: https://www.threads.com/@ryanlpeterman
• Instagram: https://www.instagram.com/ryanlpeterman
• TikTok: https://www.tiktok.com/@ryanlpeterman

Referenced in this episode:

• The Book of Why: https://en.wikipedia.org/wiki/The_Book_of_Why
• Bayesian networks: https://en.wikipedia.org/wiki/Bayesian_network
• Alpha-beta pruning: https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_pruning
• Pearl vortex: https://en.wikipedia.org/wiki/Pearl_vortex
• Graphoid: https://en.wikipedia.org/wiki/Graphoid
• Causality: Models, Reasoning, and Inference: https://en.wikipedia.org/wiki/Causality_(book)
• Coexistence and Other Fighting Words: Selected Writings of Judea Pearl, 2002–2025: https://bayes.cs.ucla.edu/COEXISTENCE/

Xavier Leroy (creator of OCaml) is an expert in compilers, formal verification of software and functional programming. This interview should be an approachable resource if you're curious about formal verification of software since I was learning that on the fly during it.

• My ergonomic keyboard project I mentioned, you can follow along here: https://read.compose.llc/
• The Kickstarter page for it: https://www.kickstarter.com/projects/ryanlpeterman/compose-simple-ergonomics-beautifully-done

Podcast links:

• YouTube: https://youtu.be/9Cswiqrq6So
• Apple: https://podcasts.apple.com/us/podcast/the-peterman-pod/id1777363835
• Transcript: https://www.developing.dev/p/creator-of-ocaml-functional-programming

Thank you to this episode's sponsor for supporting my work:

• WorkOS: makes your app Enterprise Ready with easy to use APIs to add SSO, SCIM, RBAC, and more in just a few lines of code, check them out at https://workos.com/

Timestamps:

(00:00) Intro
(00:43) What sets OCaml apart
(04:39) OCaml vs Rust
(07:57) Why is manual memory management more performant
(11:21) Javascript vs OCaml
(14:00) Famous Rob Pike quote
(16:05) Type inference and how it works
(22:12) What is formal verification and how does it work
(40:07) What made multicore support difficult for OCaml
(50:17) How programming languages interface and call each other
(57:41) The danger of almost-correct LLM code
(01:05:39) How LLMs will change programming languages
(01:10:26) Industry vs academia
(01:15:05) Most interesting unsolved problems
(01:18:30) Top book recommendations for engineers
(01:21:17) Advice for his younger self
(01:23:31) Outro

Where to find Xavier:

• Wikipedia: https://en.wikipedia.org/wiki/Xavier_Leroy
• Website: https://xavierleroy.org/

Where to find Ryan:

• Newsletter: https://www.developing.dev/
• X/Twitter: https://x.com/ryanlpeterman
• LinkedIn: https://www.linkedin.com/in/ryanlpeterman/
• Threads: https://www.threads.com/@ryanlpeterman
• Instagram: https://www.instagram.com/ryanlpeterman
• TikTok: https://www.tiktok.com/@ryanlpeterman

Referenced in this episode:

• CompCert verified C compiler: https://compcert.org/
• seL4 microkernel: https://sel4.systems/
• Programming Pearls (book, not an affiliate link): https://www.amazon.com/dp/0201657880
• How to Design Programs (book): https://htdp.org/