Evan Czaplicki (@evancz) / X

Pinned

Jun 23, 2025

Many programmers would love to use "productivity languages" like @elmlang, but what about the business person who often makes the final decision? How can we rethink our strategies such that authors, developers, and businesses grow stronger together? 🔄

Keynote: Rethinking our Adoption Strategy - Evan Czaplicki | Lambda Days 2025

Dijkstra on testing vs language design: "For what program structures can we give correctness proofs without undue labor?" With @elmlang you get: - no null pointers - no unhandled exceptions - no aliasing bugs - safety from supply chain attacks AND it's more fun than JS/TS 😅

Dijkstra points out, exhaustive testing of a computer program is virtually impossible, and testing by "sampling" also is pointless. As he says, "Program testing can be used to show the presence of bugs, but never to show their absence!" And, while rigorous mathematical proofs of program correctness are possible, they are difficult to construct, often because the programs themselves are not well suited to such analysis. So, as Dijkstra explains, rather than first writing a program and then worrying about the difficult task of constructing a proof of program correctness, it makes far better sense to ask, "For what program structures can we give correctness proofs without undue labour..." and then, "How do we make, for a given task, such a wellstructured program ?"

Going to be in NYC in November. Come to my talk at @recursecenter if you are around!

Evan Czaplicki: Dragging SQL into the 1990s · Luma

Making progress on the @elmlang 0.19.4 upgrades. Compiler improvements usually touch a high % of modules, so [128 of 153] means it's coming along nicely!

Evan Czaplicki

@evancz

Oct 26

Have you ever wondered why companies can charge $15 to send 1000 emails? I started sending emails with just a TCP connection and OpenSSL to figure it out for myself!

evancz.dev

Why is it so expensive to send an email?

Sending an email is essentially the same as making an HTTPS request, so how can companies charge $15 to send 1000 emails?

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Evan Czaplicki

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