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Re:Cgp-serde: A modular serialization library for Serde powe... by maybevoid on Friday November 14, 2025 @01:20PM (#45929928)
Author here, glad to see this featured on HN! AMA about Context-Generic Programming or Rust traits!
Re:Cgp-serde: A modular serialization library for Serde powe... by carterschonwald on Friday November 14, 2025 @01:56PM (#45930484)
How does it avoid the challenges and needed ergonomics in scala. Like I think they rolled it back for scala 3?
Re:Cgp-serde: A modular serialization library for Serde powe... by maybevoid on Friday November 14, 2025 @02:14PM (#45930775)
The providers in CGP work a little different than implicit parameters in Scala. Specifically, the provider implementations are bound to a `Context` or `Self` type during compile-time wiring. So if you know the concrete `Context` type, then you can resolve all provider implementations for that context.

Because the wiring is done globally for an explicit `Context` type, there is no issue of ambiguity that arise based on when an implicit parameter is bound. I call this scoped coherence, as it leverages incoherence for overlappable implementations, but still maintain global coherence through the wiring in a context type.