mvm-sh/mvm v0.3.0

on GitHub

mvm v0.3.0

A Go interpreter that compiles to bytecode and runs on a small stack VM — single
static binary, full standard library bundled, embeddable in Go and C.

Added

• clear builtin (maps and slices) — the last builtin mvm was missing.
• comparable as a generic constraint, plus broader generics-parsing improvements.
• mvm run <import-path> fetches and runs a remote main package; trailing args
  become its os.Args.
• mvm test runs and validates Example* functions (output checked against the
  // Output: comment), and -bench REGEX runs benchmarks through native testing.
• -stat prints compile/execute statistics on both run and test.
• interp.ExitError lets embedders catch interpreted os.Exit / log.Fatal* as a
  typed error instead of terminating the host (ADR-018).
• cmd/mvmlint, a small linter for mvm-specific code patterns.
• Stdlib bridges for encoding/gob; encoding/xml round-trips via a new xmlx
  shim (interpreted xml/Text marshalers work through native encoding/xml
  in both directions).
• Native method hooks and composite interface bridges (one interpreted type
  satisfying several native interfaces at once).
• Test infrastructure to run the Go standard library's own external _test.go
  suites against mvm's reflect bridges.

Changed

• Exit virtualization (os.Exit, log.Fatal*) is now unconditional and wired
  automatically on the first Eval (ADR-018).
• Load/parse/compile errors report file:line:col with a source snippet and a
  caret; runtime panics print a unified interpreted + native stack.
• mvm test -stat prints the stats block after the test output, just before
  PASS/FAIL.
• Build targets split: make test (race only), make cover (coverage), and a new
  make fast (-short + race) for a quick inner loop.

Fixed

Numerics (untyped-constant/float mixing, zero value, per-frame cache),
pointer-receiver method lookup and interface wrapping, type switches
(TypeBranch + interface-wrapper edges), and generics/inference (no type loss in
multi-return; inference on func-typed params), among others. Full list in
CHANGELOG.md.

Also new: a live compatibility matrix

https://mvm.sh/compat — mvm now runs the real test suites of the standard
library and ~50 popular packages through the interpreter every week and publishes
per-package pass / partial / fail with a trend over time. ~96% of individual test
cases pass today; the generator is itself a Go program run through mvm. Honest
numbers on purpose.

Try it in the browser: https://mvm.sh/playground
Install: go install github.com/mvm-sh/mvm@latest
Questions & feedback: https://github.com/mvm-sh/mvm/discussions