Kip Cole on Time, Localization and Building Agenda
Show notes
The Navajo Nation inside Arizona observes daylight saving. The Hopi reservation inside the Navajo Nation skips it again. There's a corner of the Yucatan Peninsula that takes 20 minutes to drive through and costs you an hour on your sat nav. No compiler warns you about any of this.
Kip Cole has spent 10 years building the Elixir libraries that handle what software gets wrong about human reality: localization, time, and scheduling. CLDR/ex_cldr gave the ecosystem 173,000 Unicode characters and locale-aware formatting for numbers, dates, currencies, and units. Tempo remodelled time as an interval instead of an instant. And this week, Agenda shipped - the scheduling engine four years in the making.
Topics include:
why localization is not translation - the three things that go wrong in an e-commerce search before a single word has been mistranslated
the 10-year weekend project: how a localization library for Elixir turned into 28 packages and a full rewrite into Localized
why compile-time code generation with Elixir macros hit a wall - 1,000+ function clauses and quadratic compile times - and why moving to runtime fixed it
the astronomical algorithms scar: three years of learning a new branch of mathematics to implement calendar software the BEAM was never designed for
what Tempo makes explicit that everyone does by accident: time as an interval, not an instant
why scheduling is just set intersection over everyone's free and busy intervals - and why that single insight collapses almost every hard scheduling problem
how "sometime on Tuesday" is not a time but a domain error - and what Tempo forces you to say instead
Unicode version 18, 173,000 human language characters, and why most language ecosystems still can't represent them correctly
the difference between CLDR (the Unicode standard) and Localized (the Elixir implementation of it)
what Agenda actually ships this week and what's next
Recorded September 8th, 2026.