Evolving Code Through Accretion

on YouTube ↗28m

" summary

Argues for evolving systems by accretion: keeps old functions and adds new ones to avoid breaking users, weighing migration cost against concrete gains. Describes using guardrails vs ghostwheel for immediate runtime feedback (it catches many errors early). Describes the pattern library used at New Bank to ingest services that strip namespaces, re-qualify keys, and resolve relationships like customer-id → customer-name; pattern is being rewritten (pattern3) and currently depends on spec1/spec2 compatibility decisions. Recursive specs and namespace-key strategy work in practice.

AI-written summary · about

" chapters (8)

1. 0:00Introduction and background
2. 4:22Working with Clojure Spec
3. 6:05Function naming and library evolution
4. 8:37Handling namespaced keywords
5. 12:31Project structure for specs
6. 16:38Recursive specs and namespace keywords
7. 20:27Namespace keywords as superpower
8. 24:06Future plans and open source

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