Glossary
This is not a dictionary. These are the ideas we have explored, arranged alphabetically so you may find them again.
- Abstraction
- — Finding the common pattern among specific instances. (Ch.~24: The General and the Specific)
- Branching
- — Creating alternative timelines from a common point. (Ch.~18: Forking Paths)
- Commutativity
- — The property that order does not matter. (Ch.~20: The Algebra of State)
- Effect
- — An action that reaches beyond pure computation---interacting with the outside world. (Ch.~13: Hitting a Wall)
- Event
- — A discrete occurrence that may cause the state to change. The punctuation of change. (Ch.~2: What Makes Things Happen)
- Event log
- — An append-only record of everything that happened. (Ch.~15: The Eternal Ledger)
- First-class value
- — Something that can be stored, passed, and manipulated like any other value. (Ch.~8: Verbs Become Nouns)
- Function
- — A named relationship between input and output. A small machine. (Ch.~7: The Power of Names)
- Functor
- — A container that supports transforming its contents. (Ch.~14: Possibility as Container)
- Higher-order function
- — A function that receives or returns other functions. (Ch.~9: Delegation)
- Idempotency
- — The property that applying twice is the same as applying once. (Ch.~20: The Algebra of State)
- Immutable
- — The view that things do not change; new things are derived. Parmenidean. (Ch.~3: The River and the Stone)
- Interface
- — The shared shape that different implementations fill. (Ch.~24: The General and the Specific)
- Interpretant
- — (Peirce) The mind that connects sign to meaning. (Ch.~26: The Expanded Mind)
- Merging
- — Combining divergent timelines into one. (Ch.~19: When Paths Reunite)
- Mutable
- — The view that things change in place. Heraclitean. (Ch.~3: The River and the Stone)
- Polymorphism
- — The same name having different behavior based on context. (Ch.~23: Many Faces, One Name)
- Product type
- — A type that combines several values. This AND that. (Ch.~11: And/Or)
- Pure function
- — A function that produces output from input without modifying anything. (Ch.~5: Derivation)
- Replay
- — Deriving state by re-applying events from the beginning. (Ch.~16: Replay)
- Result type
- — A union type representing success OR failure. (Ch.~13: Hitting a Wall)
- State
- — A complete description of how things are at a particular instant. The photograph of a moment. (Ch.~1: The Snapshot)
- The expanded system
- — The totality of knowledge about a system, not just its code. (Ch.~26: The Expanded Mind)
- Type
- — A category of things. What kind of thing something is. (Ch.~10: What Kind of Thing)
- Union type
- — A type that can be one of several alternatives. This OR that. (Ch.~11: And/Or)
- Validation
- — Checking whether something is allowed before doing it. (Ch.~12: The Rules of the Game)