Tscheme

Tscheme is a Lisp-derived programming language in the Scheme family, designed to combine the expressiveness of Scheme with optional static typing and predictable performance. It emphasizes a small core, a hygienic macro system, and a straightforward runtime suitable for both education and research.

Origins and goals: Tshscheme originated as a collaborative project among researchers and hobbyists to provide a typed variant of Scheme that preserves the simplicity and elegance of the original. The core language is intentionally minimal, with formal semantics and a focus on early error detection and tooling support, including type inference and gradual typing.

Key features: It includes first-class functions, lexical scoping, and tail-call optimization. The macro system supports hygienic macros and macro-by-example. An optional static type system offers type inference and gradual typing, allowing code to run untyped or with annotated types. The standard library provides lists, vectors, I/O, concurrency primitives, and lazy sequences.

Syntax and semantics: Tshcheme uses parenthesized s-expressions and a prefix notation familiar to Scheme programmers. The type system is designed to be non-intrusive, so runtime behavior remains unchanged when adding types. Tooling focuses on informative type errors, REPL-driven development, and debuggable code generation.

Implementation and use: Implementations typically compile to bytecode for a virtual machine or to native code via a JIT backend. Tshcheme interoperates with existing Scheme code and can import modules from other Scheme dialects. A small ecosystem of development tools, libraries, and educational resources supports its adoption in universities and independent learning.

Reception: Tshcheme is a niche language, mainly found in academia and among Scheme enthusiasts. It is not as widely adopted as mainstream Scheme implementations, but it is cited in discussions of typing in Lisp-family languages and in teaching functional programming.