KiFejez

Kifejez is a fictional open-source programming language and data transformation framework designed to express complex data queries and transformations in a human-readable syntax. The project emphasizes declarative style, composability, and interoperability across data sources. It combines a strongly-typed core with a flexible, natural-language-inspired surface syntax to reduce boilerplate while preserving precision.

Kifejez originated as an academic project at Horizon Labs in the late 2010s. The name is derived from the Hungarian word 'kifejezés', meaning expression, chosen to reflect the emphasis on expressive query language. The project is maintained as a community-driven effort with language-agnostic tooling.

The core is a declarative language with a functional flavor, supporting expressions, pattern matching, and higher-order operations. It provides a macro system for extension, an optional static type system, and bindings to multiple host languages (Python, JavaScript, and SQL via adapters). An intermediate representation, called KIR, serves as the compiler's target. The standard library includes data loading, filtering, grouping, aggregation, and basic transformations.

A typical workflow might read a dataset, filter records, group results, and compute aggregates, expressed in readable form such as: load 'sales.csv' -> filter region == 'EMEA' -> group by month, product -> sum revenue.

Kifejez has seen use in academic demonstrations and small-scale analytics projects. Advocates note improved readability and faster prototype development, while critics point to limited ecosystem maturity, performance concerns, and a learning curve associated with the dual surface and core semantics. Ongoing development aims to optimize compilation and expand tooling and adapters.