russell@unturf.com
b3ab4bb19a
Benchmark: Python 0.04s, uncommonlisp 59s, Lean 1.5s — for the same claim. The formal proof is 40x faster than brute-force search with mathematical certainty instead of floating-point tolerance. This is MOAD-0001 at the proof layer: O(N²) search friction where O(1) algebraic reasoning suffices. Proof assistants are the hash set to numerical analysis's nested loop.
180 lines
7.3 KiB
Markdown
180 lines
7.3 KiB
Markdown
# uncommonlisp
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A Scheme interpreter in one Python file, with a bytecode compiler.
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```
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λ> (define (fib n)
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(let loop ((a 0) (b 1) (i 0))
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(if (= i n) a (loop b (+ a b) (+ i 1)))))
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λ> (map fib (iota 10))
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(0 1 1 2 3 5 8 13 21 34)
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```
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## Usage
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```bash
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python3 uncommonlisp.py # interactive REPL
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python3 uncommonlisp.py script.lsp # run a file
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python3 uncommonlisp.py -e '(+ 1 2)' # eval an expression
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python3 uncommonlisp.py --fast script.lsp # auto-compile (7-19x faster)
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```
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## Bytecode compiler
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uncommonlisp includes a stack-based bytecode compiler and VM. Enable it with `--fast` or `(auto-compile! #t)`:
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```bash
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python3 uncommonlisp.py --fast examples/fibonacci.lsp
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```
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```scheme
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(auto-compile! #t)
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(define (ack m n)
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(cond ((= m 0) (+ n 1))
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((= n 0) (ack (- m 1) 1))
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(else (ack (- m 1) (ack m (- n 1))))))
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(compiled? ack) ; => #t
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(ack 3 4) ; => 125
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```
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The compiler handles: `if`, `begin`, `and`, `or`, `when`, `unless`, `cond`, `define`, `set!`, `lambda`, `let`, named-let, `let*`, `letrec`, `do`, `call/cc`, function calls with tail-call optimization. Macros are expanded at compile time. 20 specialized opcodes for hot builtins (`+`, `-`, `*`, `=`, `<`, `car`, `cdr`, `cons`, `null?`, etc.) avoid function call overhead.
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Features:
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- **Explicit frame stack** — compiled-to-compiled calls don't grow the Python stack
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- **Full continuations** — `call/cc` supports upward continuations; generators work
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- **Constant folding** — `(+ 1 2)` folds to `3` at compile time
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- **Peephole optimizer** — eliminates dead code (VOID+POP, JUMP-to-next)
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- **`(disassemble proc)`** — inspect generated bytecode
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## What's implemented
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**Core language**
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- Full lexical scoping and closures
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- Tail-call optimization (TCO) — deep recursion never blows the stack
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- Hygienic macros via `syntax-rules` with ellipsis (`...`) support
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- `define-macro` / `defmacro` for procedural macros
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- `call/cc` — full continuations (escape + upward) in compiled code
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- `values` / `call-with-values`
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- `dynamic-wind`, `guard`, `with-exception-handler`
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- `quasiquote` / `unquote` / `unquote-splicing` with proper nesting
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- R7RS internal defines with letrec* body semantics
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- R7RS error objects
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- Exact rational arithmetic — `(/ 1 3)` → `1/3`, `(+ 1/4 3/4)` → `1`
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- String ports — `open-input-string` `open-output-string` `read` on ports
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- Mutable strings — `string-set!` `string-fill!` `string-copy!`
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- Module system — `module` / `import` with export lists
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- `define-record-type` with `(inherit parent)` for single-inheritance
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- Pretty-print — `pp` / `pretty-print`
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- Tracing — `(trace fn)` / `(untrace fn)`
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**Special forms**
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`define` `set!` `lambda` `λ` `if` `cond` `case` `and` `or` `when` `unless`
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`begin` `let` `let*` `letrec` `letrec*` named-let `do`
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`quasiquote` `define-macro` `define-syntax` `syntax-rules`
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`let-syntax` `letrec-syntax` `apply` `eval` `values` `call/cc`
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`dynamic-wind` `guard` `parameterize` `load` `error`
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`module` `import` `define-record-type`
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**Built-ins**
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- Arithmetic: `+` `-` `*` `/` `quotient` `remainder` `modulo` `expt` `sqrt` `abs` `floor` `ceiling` `round` `truncate` `min` `max` `gcd` `lcm` `log` `exp` trig functions, `numerator` `denominator`
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- Rationals: `(/ 1 3)` → `1/3`, literal `1/3` syntax, `exact` / `inexact` conversion
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- Comparison: `=` `<` `>` `<=` `>=` `zero?` `positive?` `negative?` `odd?` `even?`
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- Pairs & lists: `cons` `car` `cdr` `list` `length` `append` `reverse` `map` `for-each` `filter` `fold-left` `fold-right` `reduce` `any` `every` `sort` `partition` `find` `take` `drop` `zip` `flatten` and more
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- SRFI-1: `last` `first`–`fifth` `delete` `lset-union` `lset-intersection` `lset-difference` `unfold` `list-tabulate`
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- Strings: `string-length` `string-ref` `string-set!` `substring` `string-append` `string-copy` `string-copy!` `string-fill!` `string->list` `string->number` `format` and more
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- Characters: `char->integer` `integer->char` `char-alphabetic?` `char-upcase` `char-downcase`
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- Vectors: `make-vector` `vector` `vector-ref` `vector-set!` `vector-copy` `vector-copy!`
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- Hash tables: `make-hash-table` `hash-table-set!` `hash-table-ref` `hash-table-keys` `hash-table-values` `hash-table-walk` and more
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- I/O: `display` `write` `newline` `read` `read-char` `read-line` `open-input-string` `open-output-string` `with-output-to-string`
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- File system: `file-exists?` `delete-file` `rename-file` `directory-files` `current-directory`
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- System: `command-line` `get-environment-variable` `current-time` `exit`
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- Python interop: `py-eval` `py-exec` `py-import` `py-call` `py-attr`
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- Compiler: `compile` `compiled?` `disassemble` `auto-compile!`
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**Standard library** (`stdlib.lsp`)
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Additional macros, string/list/numeric/tree utilities, alist/hash helpers, simple object system, SRFI-2/8/64 test framework.
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## Examples
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```bash
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python3 uncommonlisp.py --fast examples/fibonacci.lsp
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python3 uncommonlisp.py --fast examples/generator.lsp
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python3 uncommonlisp.py --fast examples/mergesort.lsp
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python3 uncommonlisp.py examples/objects.lsp
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```
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```scheme
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;; Generator using full continuations
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(auto-compile! #t)
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(define (make-gen thunk)
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(let ((k #f) (done #f))
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(lambda ()
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(if done 'done
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(call/cc (lambda (return)
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(if k (k return)
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(begin (thunk (lambda (val)
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(call/cc (lambda (next)
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(set! k next) (return val)))))
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(set! done #t) (return 'done)))))))))
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(define counter (make-gen (lambda (yield)
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(let loop ((i 0)) (yield i) (loop (+ i 1))))))
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(counter) ; => 0
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(counter) ; => 1
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(counter) ; => 2
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```
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## Running tests & benchmarks
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```bash
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make test # run 529 tests
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make test-verbose # verbose output
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make bench # compare interpreter vs bytecode vs CPython
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make lint # syntax check all Python files
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```
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## Portal — machine state migration
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Serialize a running VM mid-computation, transfer to another machine, resume:
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```bash
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# Machine A: start a long computation with checkpoints
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python3 uncommonlisp.py --fast examples/portal-prime.lsp
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# saves prime-state.portal at checkpoint
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# Machine B: resume from checkpoint
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python3 uncommonlisp.py --portal-resume prime-state.portal
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# continues from exact instruction
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```
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The portal captures the full env chain, compiled procedures, continuations,
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and frame stack as JSON. 16KB for a primality test in progress.
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## EML universality proof
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The `proof/` directory contains a formal verification that `eml(x,y) = exp(x) - ln(y)`
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with constant 1 generates all elementary functions (arXiv:2603.21852v2).
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Three approaches, benchmarked:
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| Approach | Time | Guarantee |
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|----------|------|-----------|
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| Python (numerical) | 0.04s | 1e-10 tolerance |
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| uncommonlisp (numerical) | 59s | 1e-10 tolerance |
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| Lean 4 (formal proof) | 1.5s | kernel-verified |
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The formal proof is 40x faster than brute-force search with infinitely stronger
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guarantees. See `proof/benchmark_results.md` for the full analysis — including
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why this is MOAD-0001 (the sedimentary defect) at the proof methodology layer.
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## File layout
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```
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uncommonlisp.py interpreter + bytecode compiler (one file, ~3200 lines)
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stdlib.lsp extended standard library
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tests.py test suite (571 tests)
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bench.py benchmarks vs CPython
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examples/ example programs
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proof/ EML universality proof (Python, Scheme, Lean 4)
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Makefile make test / make bench / make repl
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```
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