Concurrency

Clef’s concurrency model is built on delimited continuations. This primitive replaces the colored-function problem of traditional async/await with a single mechanism for suspension, resumption, and structured concurrency.

CCS/Baker settle a region’s dependencies, effects, demand, joint constraints and admitted execution regime on the PSG. Sequential effects use continuation aggregates; admitted independent work may use tensor structure or interaction-net reductions according to its shape and proof premises. Alex’s Library of Alexandria passively witnesses that immutable publication through Huet Elements/Patterns/Witnesses. Composer’s backend owns the selected target realization.

These articles trace how that foundation was chosen and how the compiler lowers async Clef code to native continuations without a managed runtime, from the divergence with .NET’s async lineage to liveness across actor boundaries carried as a visible compile-time obligation. The same reading of a region’s structure decides whether its concurrent strands merely reorder or cross in an order the runtime can observe, the distinction the braid work lifts into the type system.

Our seventh preprint, Coexponential Exploration in the Clef Programming Language, develops the formal account behind these actor boundaries. Start with the Three-Layer Actor Contract for data, protocol and liveness, Delimited Continuations for suspension, and Ariel Under Prospero for the execution premises. The paper separates the finite service model and its preservation obligations from the broader session-inference and implementation work still ahead.