ltype

Ltype is a conceptual programming language and type system used in academic discussions of linear and affine types to explore safe resource management and ownership models. It emphasizes compile-time guarantees about how values are created, moved, and consumed, with the goal of reducing runtime overhead while preventing common resource bugs.

Ltype employs linear and affine typing to differentiate values that must be used exactly once from those that may be reused. It supports algebraic data types, pattern matching, and a small, inference-assisted syntax. The language provides explicit notions of ownership, borrowing, and lifetimes, plus a lightweight memory model suitable for embedded and real-time contexts. Generics and higher-order functions exist but are restricted to preserve safety.

In Ltype, functions may take linear parameters; returning values transfers ownership, while unrestricted values can be copied. Borrowing allows temporarily sharing references with static checks. The model aims to prevent several classes of bugs such as use-after-free, double-free, and data races at compile time.

Ltype exists primarily in academic prototypes and teaching materials, rather than as a widely used production language. Reference implementations demonstrate concepts with backends to LLVM or bytecode engines, and it has influenced discussions around resource-safe design in other languages.

See also: Rust, affine types, linear logic, ownership types, and type systems for memory safety.