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Demo: Implicit Context

Jonathan Blow · 28K views · 2015-05-21 · 1:01:40

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Overview

Jonathan Blow gives a formal, hour-long demo of his Jai compiler focused on the implicit context feature. The context carries things like allocators through a program without explicit parameter passing, and the talk walks through the code.

On Hacker News

Cited in discussions of memory arenas and allocators as the origin of the implicit context idea that later appeared in Odin and other languages.

Recommended by 1 HN people across 1 months · HN mentions 2022–2025

Topics

Programming language designCompilers, interpreters & program analysis
Search by tags
jaiimplicit contextallocatorscompilerssystems programming

What people said

nmilo · 2025-12 · Recommendation

Implicit context [1] was one of the coolest features of a programming language I’ve ever seen that no one has ever implemented. And I’m really not sure why. Not just Go but most languages have this context passing problem with varying degrees of solution quality, making this implicit and built in could have opened up so many possibilities, more than just arenas. [1]: [VIDEO]

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rudedogg · 2022-11 · Reference

> per-frame "scratch" pool allocator Here's that Jonathan Blow stream if anyone else is curious: [VIDEO]

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cyber_kinetist · 2022-09 · Reference

I remember first seeing this idea from Jai ( [VIDEO] ), and I'm happy it's landing in other languages. Zig went another direction and requires you to specify the allocator explicitly via a function parameter, which is understandable given the language's goal to make everything explicit.

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Sources

Video by Jonathan Blow, played through YouTube.

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