







Three Sets of Specs (for Staying in Spec) In the last post I talked about how systems formalisms are like sculpting with a chisel: we remove behaviors we don’t…
The Spec Can Come Later - The Phoenix Architecture
When I say things like "delete the code, keep the spec," many people seem to interpret that as a rule: write the specification first, and only then are you a…
The Spec Can Come Later - The Phoenix Architecture
When I say things like "delete the code, keep the spec," many people seem to interpret that as a rule: write the specification first, and only then are you a…
Symmetric lenses | Proceedings of the 38th annual ACM SIGPLAN-SIGACT symposium on Principles of programming languages
A lens is a bidirectional transformation between a pair of connected data structures, capable of translating an edit on one structure into an appropriate edit on the other. Many varieties of lenses have been studied, but none, to date, has offered a ...

oracle/agent-spec
Open Agent Spec (Agent Spec) is a framework-agnostic declarative language for defining agentic systems. It defines building blocks for standalone agents and structured agentic workflows as well as common ways of composing them into multi-agent systems.
Specs 2
Specs 2 is an ecosystem for specs driven component development. Via the plugin, turn a selected Figma component or component set into a compact, complete, schema-valid specification — computed directly from the file, not inferred from a screenshot. From the command line, generate specs from an en...
Quotient lenses | Proceedings of the 13th ACM SIGPLAN international conference on Functional programming
Bidirectional programming languages are a practical approach to the view update problem. Programs in these languages, called lenses, define both a view and an update policy - i.e., every program can be read as a function mapping sources to views as well ...

Categories of Optics
Bidirectional data accessors such as lenses, prisms and traversals are all instances of the same general 'optic' construction. We give a careful account of this construction and show that it extends to a functor from the category of symmetric monoidal categories to itself. We also show that this construction enjoys a universal property: it freely adds counit morphisms to a symmetric monoidal category. Missing in the folklore is a general definition of 'lawfulness' that applies directly to any optic category. We provide such a definition and show that it is equivalent to the folklore profunctor optic laws.

What you needa know about Yoneda: profunctor optics and the Yoneda lemma (functional pearl) | Proceedings of the ACM on Programming Languages
Profunctor optics are a neat and composable representation of bidirectional data accessors, including lenses, and their dual, prisms. The profunctor representation exploits higher-order functions and higher-kinded type constructor classes, but the ...

When Does a Specification Become a Program? - The Phoenix Architecture
A spec can contain prose, tests, schemas, formal models, even executable code. The useful boundary is not the syntax but, rather, what survives: if you throw the implementation away, what has to remain so you can build the next one?
When Does a Specification Become a Program? - The Phoenix Architecture
A spec can contain prose, tests, schemas, formal models, even executable code. The useful boundary is not the syntax but, rather, what survives: if you throw the implementation away, what has to remain so you can build the next one?
Designing Systems | Atomic Design by Brad Frost
Learn how to create and maintain digital design systems, allowing your team to roll out higher quality, more consistent UIs faster than ever before.

Dependent Optics
A wide variety of bidirectional data accessors, ranging from mixed optics to functor lenses, can be formalized within a unique framework-dependent optics. Starting from two indexed categories, which encode what maps are allowed in the forward and backward directions, we define the category of dependent optics and establish under what assumptions it has coproducts. Different choices of indexed categories correspond to different families of optics: we discuss dependent lenses and prisms, as well as closed dependent optics. We introduce the notion of Tambara representation and use it to classify contravariant functors from the category of optics, thus generalizing the profunctor encoding of optics to the dependent case.

panproto/crates/panproto-lens-dsl at main · panproto/panproto
One engine for schematic version control within and across any schema language. - panproto/panproto
When Does a Specification Become a Program? · The Phoenix Architecture
A spec can contain prose, tests, schemas, formal models, even executable code. The useful boundary is not the syntax but, rather, what survives: if you throw the implementation away, what has to remain so you can build the next one?
