Explicit Namespaces1

A namespace is a mapping from labels to values. Most programming languages support different forms of namespaces, such as records, dictionaries, objects, environments, packages and even keyword-based parameters. Typically only a few of these notions are first-class, leading to arbitrary restrictions and limited abstraction power in the host language. Piccola is a small language that unifies various notions of namespaces as first-class forms, or extensible, immutable records. By making namespaces explicit, Piccola is easily able to express various abstractions that would normally require more heavyweight techniques, such as language extensions or meta-programming.