Kilometerlang

Kilometerlang is a fictional domain-specific programming language designed to explore unit-aware computation in distance-sensitive applications, such as geographic information systems and routing problems. It appears in online hobbyist discussions as a thought experiment to illustrate how explicit unit semantics can reduce errors in distance calculations and data flows.

The design centers on the kilometer as the canonical unit of measure. Core types include Distance, Position, and Route, with the base unit defined as km. Non-kilometer units, such as meters or miles, can be created through explicit conversions rather than implicit coercions, a choice intended to enforce clarity and prevent unit mismatches.

Key features attributed to kilometerlang include literal distance values expressed in kilometers, arithmetic operators for addition and scaling, and primitives to compose routes. A minimal standard library is often described as providing haversine-distance calculations between coordinates, total route length, and simple speed-based time estimates. The language concept emphasizes clear, traceable unit handling and explicit conversions to support debugging and verification in geospatial workflows.

In practice, kilometerlang remains a niche or hypothetical construct used in theoretical discussions and teaching to illustrate unit-safe design in domain-specific languages. It has no widespread implementation for production use, and its influence is mainly pedagogical, serving as a case study for how language design might prevent common unit-related errors.

See also: domain-specific language, esoteric programming language, geographic information systems, units of measurement.