PicoLisp
Alexander Burger’s Lisp, in development since 1988 and used in commercial work throughout. The wiki states the design as a single sentence about representation: “PicoLisp has one single internal data type: The cell.” Three types are visible at the language level — numbers, symbols, cons pairs — and all of them are cells. The claim attached is orthogonality and transparency: “nothing is hidden behind the scenes.” Pil21, the current line, is an interpreter written in PicoLisp that emits LLVM IR, and it runs on Linux, macOS, Windows via WSL, and Android through the PilBox app. The system ships an object-oriented database with persistence, a web GUI, namespaces, coroutines, dynamic native C calls, and editor integration.
T1 — first-party project wiki. It is also unusually candid for a first-party source: the pitch is a representation choice, not a benchmark, and there are no adoption numbers to distrust.
Minimalism, third reading
scheme removes features so users can build them. lua removes a category, keeping tables as the only composite. PicoLisp goes one level lower and removes the distinction between representations: one cell underneath everything. Same family as lisp and the same inheritance (common-lisp and clojure are the other dialects here), spent on being small rather than on being extensible or being hosted.
The three positions are worth holding together, because they are answers to different questions. Scheme’s is about the language definition, Lua’s about the type system, PicoLisp’s about the machine model — and only the last is a claim about what memory looks like at runtime.
What it bundles, and the company it keeps
A database and a GUI in the language distribution puts PicoLisp beside erlang and OTP, which is not a comparison anyone would predict. Both refuse the usual split between “the language” and “the libraries you will need anyway”, and both come from long-running commercial deployment rather than from a foundation or a committee. Coroutines land where lua‘s do on concurrency-model: scheduling handed back to the program.
Compiling by generating LLVM IR from an interpreter written in itself is the corpus’s most compact example of the self-hosting tradition lisp started in 1962 — and, next to nim emitting C, a second case of a small language borrowing a large toolchain instead of building a back end.
Related
lisp · common-lisp · scheme · lua · erlang · nim · concurrency-model · programming-language · synthesis