Heh 𓁨 v1.0.1 — VM by default, clean recursion faults, four platforms

Heh 𓁨 v1.0.1

A patch release. The frozen v1.0 language surface is unchanged — this is
entirely implementation work, plus the first crates.io publish.

The bytecode VM is now the default, and covers the whole language

heh run executes on the bytecode VM; --tree-walk selects the reference
tree-walking evaluator. The VM previously punted three construct families back
to the tree-walker. It now encodes all of them:

• Closures become the same function value a named function is, capturing
  the live scope.
• Optional narrowing gets real block scopes, including the case where a
  break or continue jumps out of a narrowed block.
• Field and index assignment (p.x = v, l[i] = v, and nesting). Compound
  forms duplicate the container and index rather than re-evaluating the index,
  so an index expression's side effects cannot run twice.

Both engines share one call path and one set of field/index accessors, so they
cannot drift. Output remains byte-identical across the entire conformance
corpus, enforced by a differential test.

Runaway recursion is a fault, not a crash

Deep recursion used to abort the process with fatal runtime error: stack overflow and a core dump. SPEC §7.3 says a fault stops the program with a
diagnostic. Programs now run on a dedicated 256 MB stack with a call-depth
limit of 10,000, and both engines report E0202 identically. Legitimate deep
recursion — 9,000 frames — works fine.

Performance, honestly

benches/run.sh runs five benchmarks, each paired with an equivalent CPython
program whose answer must match before a timing is reported.

benchmark	VM	tree-walk	CPython	VM vs tree-walk	VM vs CPython
fib	112ms	254ms	37ms	2.27x	0.33x
loop_sum	714ms	967ms	223ms	1.35x	0.31x
strings	52ms	56ms	53ms	1.08x	1.02x
maps	206ms	208ms	58ms	1.01x	0.28x
bigint	10ms	11ms	31ms	1.10x	3.10x

The VM beats the tree-walker on every benchmark, and beats CPython only on
arbitrary-precision arithmetic. The original design target was ≥5× CPython, and
this release does not meet it. The reason is structural rather than a
matter of tuning: every variable access is a string-keyed hash lookup up a
scope chain, and every integer heap-allocates, with no machine-word fast path —
something SPEC §5.1 explicitly invites an implementation to add. That is the
next performance milestone; the measurement harness now exists to prove it.

Also fixed

• heh fmt mangled a closure nested inside a function, emitting a body at the
  wrong indentation that would not re-parse.

Install

cargo install heh-lang     # the crate is heh-lang; the command is heh

The crate is published as heh-lang because heh was taken on crates.io
in 2022 by an unrelated project. The installed command is still heh.

Or download a binary below — linux x86_64, Windows x86_64, macOS arm64 and
x86_64. Checksums in SHA256SUMS.txt.

License

MIT © Mohamed Mounir (Lord1Egypt)