Nominalpl

Nominalpl is a statically typed, general-purpose programming language conceived as a practical exploration of nominal typing and safe concurrent programming. It is presented here as a hypothetical language used to illustrate design choices common in modern language theory.

Nominal typing means types are identified by explicit names rather than by their structure. Nominalpl enforces encapsulation through a module system that controls visibility and aliasing. The language supports interfaces (traits) that declare capabilities by name, with nominal evidence required for implementation. Generics provide parametric polymorphism with constraints.

Concurrency and safety are central to Nominalpl. It emphasizes data race prevention by offering lightweight asynchronous tasks, channels for message passing, and strict isolation of mutable state between modules. The ownership model is not as strict as in some systems languages but uses Transferable Capabilities to limit aliasing.

Syntax and tooling follow a modern, pragmatic approach. The syntax is C-like with braces, but adds conveniences such as optional type inference and a minimal syntax for pattern matching. Key keywords include fn, let, type, and mod. The standard library emphasizes portability and a stable ABI. A reference compiler, a package manager, and a test framework accompany the ecosystem.

Example:

fn add(a: int, b: int) -> int {

a + b

}

History and community: The language originated in academic discussions around 2022 and has since appeared in open-source tutorials and courses. Adoption remains modest, but Nominalpl is used in demonstrations of nominal type systems and safe concurrency models.

See also: Nominal typing, Type systems, Concurrency models, Programming language design.

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