Expressiondriven

Expressiondriven is a term used in software design to describe a paradigm in which program logic is organized primarily around expressions—formal constructs that denote values or computations—rather than explicit imperative procedures. In an expressiondriven system, computations are expressed as evaluable expressions, and a runtime engine evaluates these expressions to produce results.

Key characteristics include composability, referential transparency, and a preference for declarative construction of logic. Expressions may be nested, transformed, and composed to form larger computations. Many expressiondriven approaches emphasize lazy evaluation, incremental recomputation, and isolation of side effects to improve predictability and testability.

It shares aspects with declarative programming, functional programming, and data-driven styles, but distinguishes itself by treating expressions as the primary unit of logic and by enabling expression-centric pipelines and bindings. Unlike traditional imperative code, expressiondriven design often seeks to minimize mutable state and explicit control flow.

Applications appear in spreadsheets and formula-based tools, functional reactive programming, declarative UI frameworks, and query languages where expressions drive data flow and UI updates. It also appears in configuration systems and DSLs used for data transformation, visualization, and rule specification.

Expressiondriven is not a widely standardized term but has emerged in discussions about declarative and expression-oriented programming. It describes a trend toward tooling and languages that treat user-defined expressions as first-class citizens in specifying behavior.

See also data-driven, declarative programming, functional programming.