Elements of Clojure

Bolded terms, and their relationships, from Z. Tellman, Elements of Clojure. Monee, IL: Lulu.com, 2019.

Collections

eoc:Names

eoc:Idioms

eoc:Indirection

eoc:Composition

Concepts

eoc:accrete

rdf:type: skos:Concept

skos:definition: "To accrete is to add to an existing collection. It is one of three things a process can do with data. "

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "accrete"

eoc:adaptable

rdf:type: skos:Concept

skos:definition: "Describes a system that has sparse and flexible relationships between its modules."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "adaptable"

eoc:assumption

rdf:type: skos:Concept

skos:definition: "Something the model does not reflect as a specific facet of the environment and thus considers fixed or irrelevant."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "assumption"

eoc:cartesian%20product

rdf:type: skos:Concept

skos:definition: "Every possible combination of (elements from sequences) *a* and *b*, e.g. (for [a [1 2 3] b [:a :b :c]] [a b])."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "cartesian product"

eoc:channel

rdf:type: skos:Concept

skos:definition: "A channel is a means of indirection via which we can communicate with a process."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "channel"

eoc:closed

rdf:type: skos:Concept

skos:definition: "The need to change the decision process of a conditional by changing the underlying code."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "closed"

eoc:conditional

rdf:type: skos:Concept

skos:definition: "A conditional is any expression that uses an *if* or *case* form, making its behavior dependent on the input values."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "This is necessary when only a subset of possible values is valid or, more generally, when different subsets of possible values have different semantics."

skos:prefLabel: "conditional"

eoc:consistent

rdf:type: skos:Concept

skos:definition: "A consistent name is easily understood by someone familiar with the surrounding code, the problem domain, and the broader programming-language ecosystem."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "Consistency can minimize the continuous state of low-level confusion that exists for any project involving multiple people."

skos:prefLabel: "consistent"

eoc:contingent

rdf:type: skos:Concept

skos:definition: "The nature of conclusions we draw from inductive reasoning. They are allowed to be wrong."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "contingent"

eoc:convention

rdf:type: skos:Concept

skos:definition: "Something that helps us enforce assumptions that we cannot automatically enforce either because the assumptions are flawed or because building or executing an additional layer of abstraction is too expensive."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "convention"

eoc:data%20scope

rdf:type: skos:Concept

skos:definition: "Any data we can see from within our thread."

skos:example: "function parameters, closed-over values"

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "data scope"

eoc:dereferencing

rdf:type: skos:Concept

skos:definition: "Getting the referent value to which a reference value points."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "dereferencing"

eoc:descriptor

rdf:type: skos:Concept

skos:definition: "The output of the transform phase of a process. In general this is not just data, but rather a description of the effects that the process should perform. The push phase acts on the descriptor."

skos:example: "In the simplest case, the descriptor is only the data that should be pushed. When we pass \"hello world!\" to *print*, we give a literal description of what *print* should write to *stdout*."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "descriptor"

eoc:discovery

rdf:type: skos:Concept

skos:definition: "Fetching a list of processes able to provide a particular service."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "In practice, there is little difference between resolution and discovery."

skos:prefLabel: "discovery"

eoc:dynamic%20dispatch

rdf:type: skos:Concept

skos:definition: "Association a method with an implementation at runtime."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "dynamic dispatch"

eoc:effect

rdf:type: skos:Concept

skos:definition: "A change to a reference shared between processes."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "Shared references are often hidden behind an interface, which provides structure around how and when effects occur."

skos:prefLabel: "effect"

eoc:environment

rdf:type: skos:Concept

skos:definition: "Everything else in a module that is not model or interface: other software components, the users, and the world they exist in."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "environment"

eoc:execution%20model

rdf:type: skos:Concept

skos:definition: "A strategy describing what a process will do when its environment provides too much or too little when the process attempts to pull or push."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "A process with a well-defined execution model can be safely considered in isolation."

skos:prefLabel: "execution model"

eoc:framework

rdf:type: skos:Concept

skos:definition: "Something that invokes our code rather than being invoked by it."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "framework"

eoc:functional

rdf:type: skos:Concept

skos:definition: "A functional phase deals with code at rest and defines the purpose of a process."

skos:example: "The transform phase is functional. It can safely ignore much of the context that book-ending pull and push phases wrap in invariants."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "functional"

eoc:identifier

rdf:type: skos:Concept

skos:definition: "A process identifier is a means of indirection via which we can refer to a process."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "identifier"

eoc:identity

rdf:type: skos:Concept

skos:definition: "The identity value for a monoid is the value that, when passed to the monoid's 2-arity function along with another value, will result in the function returning the other value."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "identity"

eoc:indirection

rdf:type: skos:Concept

skos:definition: "A layer of indirection separates *what* something does from *how* it does it."

skos:example: "A function's name can be a layer of indirection."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "indirection"

eoc:interface

rdf:type: skos:Concept

skos:definition: "The means by which the model and environment interact."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "interface"

eoc:invariant

rdf:type: skos:Concept

skos:definition: "Something a model must enforce to preclude one or more invalid states that it can represent."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "invariant"

eoc:model

rdf:type: skos:Concept

skos:definition: "A collection of data and functions."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "model"

eoc:module

rdf:type: skos:Concept

skos:definition: "A model, an interface, and an environment."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "module"

eoc:monoid

rdf:type: skos:Concept

skos:definition: "A 0-arity function that returns an identity value and a 2-arity function that takes two values of the same type and returns a single combined value. Combining the identity value with any other value (the 1-arity case) returns that value unchanged."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "monoid"

eoc:narrow

rdf:type: skos:Concept

skos:definition: "A narrow name clearly excludes things it cannot represent."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "narrow"

eoc:natural

rdf:type: skos:Concept

skos:definition: "A natural name often has a rich, varied collection of senses. That is, a natural name is often ambiguous."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "natural"

eoc:necessary

rdf:type: skos:Concept

skos:definition: "The nature of conclusions in formal deductive reasoning. If such conclusions are wrong, it's only because initial assumptions were wrong."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "necessary"

eoc:open

rdf:type: skos:Concept

skos:definition: "The ability to change the behavior of dereferencing code by conveying different values."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "open"

eoc:operational

rdf:type: skos:Concept

skos:definition: "An operational phase deals with code in motion and defines the limits of a process."

skos:example: "The push and pull phases of a process are operational. They enforce invariants that can only be designed and judged given a specific context."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "operational"

eoc:phase

rdf:type: skos:Concept

skos:definition: "A component of a process that can be considered separately from the others, in isolation. A process is composed of pull, push, and transform phases."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "phase"

eoc:principled

rdf:type: skos:Concept

skos:definition: "Describes a system that has predictable relationships between its modules."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "principled"

eoc:process

rdf:type: skos:Concept

skos:definition: "The smallest unit of standalone computation. A process has execution isolation (*when* it runs), data isolation (*where* it runs), and is sequential."

skos:example: "Examples of processes: threads in modern operating systems, chains of asynchronous callbacks, Erlang's processes, Carl Hewitt's actors, Smalltalk-72's objects. These all communicate via asynchronous message passing."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "process"

eoc:protocol

rdf:type: skos:Concept

skos:definition: "The formal mechanism by which we accomplish and acknowledge tasks."

skos:example: "Communication protocols like TCP and HTTP dictate the mechanism and failure modes for communication across a single edge of our system topology."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "protocol"

eoc:pull

rdf:type: skos:Concept

skos:definition: "A process may pull data from its environment. For a process to transform data sourced from its environment, that data must first be pulled into the process."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "pull"

eoc:push

rdf:type: skos:Concept

skos:definition: "A process can push a result to its environment, for example the result of transforming data it has pulled in from its environment."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "push"

eoc:reduce

rdf:type: skos:Concept

skos:definition: "To reduce is to discard information from an existing collection. It is one of three things a process can do with data. "

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "reduce"

eoc:reference

rdf:type: skos:Concept

skos:definition: "A means of pointing at a referent."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "reference"

eoc:referent

rdf:type: skos:Concept

skos:definition: "The thing to which a name refers/points."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "referent"

eoc:referential%20transparency

rdf:type: skos:Concept

skos:definition: "An expression and its result are interchangeable."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "Laziness relies on this."

skos:prefLabel: "referential transparency"

eoc:referentially%20opaque

rdf:type: skos:Concept

skos:definition: "When we can't just focus on *what* an expression returns -- we also have to think about *how* it produces the value."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "referentially opaque"

eoc:reshape

rdf:type: skos:Concept

skos:definition: "To reshape is to place in a different kind of collection. It is one of three things a process can do with data. "

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "reshape"

eoc:resolution

rdf:type: skos:Concept

skos:definition: "A mechanism via which an identifier is mapped onto a specific process."

skos:example: "DNS resolution maps domain names onto IP addresses."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "Resolution mechanisms designed for large systems allow for basic load balancing and failover behavior by providing a one-to-many mapping between identifiers and processes."

skos:prefLabel: "resolution"

eoc:router

rdf:type: skos:Concept

skos:definition: "A mechanism that provides indirection by exposing a single channel and distributing the data on that channel across multiple processes."

skos:example: "One example is a thread pool: functions are placed on a shared queue and distributed to threads that execute them."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "router"

eoc:satisfices

rdf:type: skos:Concept

skos:definition: "A model that may not be optimal, but that works well enough in practice, satisfices."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "satisfices"

eoc:selfconscious

rdf:type: skos:Concept

skos:definition: "Describes a culture in which design and construction is a specialized task, taught in schools using abstract principles."

skos:example: "Skyskrapers, stadiums."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: " The structures of a selfconscious culture are principled; they are not meant to change. If the environment changes, the structure is hardened against the change rather than adapting to it."

skos:prefLabel: "selfconscious"

eoc:sense

rdf:type: skos:Concept

skos:definition: "The sense of a name is *how* it is referenced, the set of fundamental properties we ascribe to it."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "When we encounter a new name, we only need to understand its sense. The underlying implementation, the referent, can change without us ever knowing or caring."

skos:prefLabel: "sense"

eoc:sign

rdf:type: skos:Concept

skos:definition: "The textual representation of a name."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "sign"

eoc:spawning

rdf:type: skos:Concept

skos:definition: "A mechanism may start a new process each time it is triggered. This is spawning. That is, rather than there being a single process, multiple processes are spawned and execute concurrently."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "spawning"

eoc:static%20dispatch

rdf:type: skos:Concept

skos:definition: "Association a method with an implementation at compile time."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "static dispatch"

eoc:synthetic

rdf:type: skos:Concept

skos:definition: "A synthetic name has no intuitive sense in the context of our code."

skos:example: "Category theory is a rich source of synthetic names. 'Monad', to most readers, means nothing. As a result, we can define it to mean anything."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "Synthetic names turn comprehension into a binary proposition: either you understand it or you don't."

skos:prefLabel: "synthetic"

eoc:system

rdf:type: skos:Concept

skos:definition: "A composition of processes."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "system"

eoc:table

rdf:type: skos:Concept

skos:definition: "A data structure with a distinct set of unordered keys, used to implement an open decision-making mechanism."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "table"

eoc:task

rdf:type: skos:Concept

skos:definition: "A task is something that begins when a command enters a system and that ends when the consequences of an effect are uncertain. The completion of a task is the ultimate goal of any push, whereas the proximate goal of any push is communication."

skos:example: "A task might be started by a keystroke, a packet from the network, or the creation of the system. A task might end when we can't dictate how a user will respond after displaying text on a screen, or when we can't dictate if a value will ever be read after writing it to a database."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "task"

eoc:topology

rdf:type: skos:Concept

skos:definition: "The topology of a system is the graph describing the set of active processes and the relationships between them."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "topology"

eoc:transform

rdf:type: skos:Concept

skos:definition: "A process can transform data."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "transform"

eoc:unselfconscious

rdf:type: skos:Concept

skos:definition: "Describes a culture in which design and construction is taught using direct demonstration and reflects the constraints and variation of an environment."

skos:example: "In building igloos, there is no \"architect\" -- each person builds their own home."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:note: "The structures of an unselfconscious culture are adaptable; they reflect the present needs of the inhabitants."

skos:prefLabel: "unselfconscious"

eoc:utilization

rdf:type: skos:Concept

skos:definition: "The utilization of a state container is a measure of how often it is in the process of being updated."

skos:inScheme: https://donnywinston.com/elements_of_clojure

skos:prefLabel: "utilization"