brisk

brisk is a small strict language with row-polymorphic records and variants, an affine discipline over resources, and one canonical printed form. M0 plans the front end, the type checker, a stack VM and a driver, with no dependency outside the OCaml standard library. Through Stage D, the front end, checker and VM run through the test executables. Stage D is in progress. Lowering reconciles record order and variant tags across annotations, calls, results and branches, including nested payloads and higher-order functions (SPEC.md section 10). Row-reader offsets survive currying, partial application, captures and recursive groups. Unsupported open-row transport is refused before emission. Result layouts pass into control-flow arms and curried bodies so redundant conversions preserve tail calls when caller and callee result layouts agree. Recursive groups settle a common order for supported record and variant layouts, including annotated members and nested payloads. Closed variant matches preserve source arm order across literal payload tests and catch-all arms. A named fallback receives the original variant. Nested closed variant payload patterns use the same ordered dispatch. Failed inner tests resume enclosing alternatives with their original scope. Closed record match patterns select fields by label and occurrence, including nested record, variant and literal tests. Failed fields resume the next arm without retaining that arm's bindings. Record rest bindings and match scrutinees with visible open-row reader types remain refused. The assembler preserves lexical bindings and captures across temporary argument pushes, including nested lets, matches and recursive groups. The driver arrives at Stage E. The grammar, the tree and the printer are a rewrite, not a port. SPEC.md holds the surface syntax, the refusal table of the forms that arrive at M1 and at M2, and the error line form.

Layout

brisk/
  dune-project (lang dune 3.24) (name brisk);  README.md SPEC.md
  LICENSE-MIT LICENSE-APACHE
  lib/  brisk_core: ident.ml label.ml literal.ml row.ml types.ml kind.ml
        subst.ml unify.ml level.ml env.ml error.ml pp.ml ir.ml primop.ml
  surface/  brisk_surface: lexer.ml parser.ml ast.ml print.ml infer.ml lower.ml
  vm/  brisk_vm: instr.ml value.ml assemble.ml exec.ml prim.ml census.ml
  test/  main.exe (check suite), vm.exe (run suite), parse.exe (round trip)
         refusals.exe (checked programs rejected during lowering)
  dev/  bench.sh denominators.sh denominators.json DENOMINATORS.sha256 gates.sh
        pin-dune.sh house.sh trusted-lines.sh PROVENANCE.md M0-BUILD-LOG.md
        MUTATION-LOG.md
  test/vm/  machine programs and hand-written stdout goldens
  test/lower-neg/  lowering refusals and exact diagnostic goldens
  examples/m0-spine.bk  the placeholder numerator corpus until Stage E

The checker handles types, rows, schemes and the M0 refusal table. Lowering converts checked programs to a core IR with fifteen arms and explicit closure captures. The VM executes the closed set of twenty-two instructions, including partial application, record offsets, variant switches and tail calls. SPEC.md section 10 describes the machine.

Build and gate

The OCaml switch is pinned. Every command runs through the pin runner, so no build reads a package outside the switch:

zsh dev/pin-dune.sh dune build @all
zsh dev/gates.sh
zsh dev/gates.sh --leg suite-vm
zsh dev/gates.sh --leg trusted-lines

The battery through Stage D has seven legs. BUILD holds dune build @all clean. HOUSE holds the house rules of the plan section 11 over lib, surface and vm, plus test. PARSE holds parse, print, parse and print equal on its 46 fixtures. SUITE-CHECK requires at least 19 positive fixtures and 37 negative twins. SUITE-VM checks the stdout goldens of every program with main in test/vm and test/pos, with a floor of 181 programs. It requires at least fifteen lowering refusals to parse and check successfully before matching their exact diagnostic goldens; the tree ships fifteen. SUITE-VM also requires all 22 instructions to be emitted and executed, and the 100,000-call tail recursion fixture and twenty-nine named layout and match regressions to use at most 64 stack slots each. TRUSTED-LINES requires all counted files to exist and holds the six core files at 2,000 lines and the three machine files at 800. DENOMINATORS re-measures the raw compile rate of the machine, so every timing number of a log is a ratio against the run that produced it.

Licence

MIT OR Apache-2.0. See LICENSE-MIT and LICENSE-APACHE.

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