RuleMonkey 3.9.0

[3.9.0] — 2026-08-07

Added

• Windows / MSVC is now a CI gate (issue #29). The build job runs
  ubuntu-latest, macos-latest and windows-latest; the Windows leg
  configures, compiles with MSVC 14.51 and passes all 30 ctest cases in
  under two minutes. Before this, no part of RuleMonkey had ever been
  compiled with MSVC — the code's _MSC_VER guards were an assessment from
  reading the source, not a tested claim, and one of them was missing (see
  below).

  All three legs share the same Ninja release preset. A multi-config
  Visual Studio generator would leave CMAKE_BUILD_TYPE empty and silently
  change which self-check defines compile in, so the Windows leg instead
  puts the MSVC environment on PATH first — the hosted image does not
  expose cl.exe to a non-VS generator, and CMake would otherwise
  configure against whatever compiler it found (the Strawberry Perl gcc).

  Two MSVC-only compile flags come with it, applied directory-wide and
  gated on MSVC so the Clang/GNU -Wall -Wextra -Werror sets are
  untouched: /bigobj, without which the vendored exprtk translation unit
  stops at fatal error C1128, and /utf-8, which pins source decoding so
  RM's non-ASCII diagnostic strings do not depend on the build machine's
  active code page. The tree compiles clean at MSVC's default /W3 — zero
  warnings.

  The asan job stays ubuntu/macos: -fsanitize=address,undefined is the
  GCC/Clang spelling, MSVC ships no UBSan, and CMakeLists.txt already
  refuses RULEMONKEY_ENABLE_ASAN outside Clang/GCC.

Changed

• CI workflow actions moved off Node 20 (issue #30). actions/checkout,
  actions/setup-python and actions/upload-artifact are on v7. The two pins
  with no Node 24 version were retired rather than bumped:
  seanmiddleditch/gha-setup-ninja is gone entirely — it is archived upstream
  and its latest release is still Node 20, while all three runner images ship
  Ninja 1.13.2 on PATH — and the MSVC environment now comes from a vswhere +
  vcvars64.bat step rather than ilammy/msvc-dev-cmd, every available
  MSVC-environment action being Node 20 as well. A full run now carries no
  deprecation annotations on any job.

  Build pipeline only: no engine, API or build-system behaviour changes for a
  consumer of the library.

Fixed

• __builtin_popcount made the engine uncompilable with MSVC.
  build_nary_partitions, which pre-expands the Möbius coefficients for a
  rule with three or more reactant patterns, reached for the GCC/Clang
  builtin with no _MSC_VER counterpart — unlike highest_pow2 a few lines
  above it, which carries GCC/Clang, MSVC and generic branches — so cl.exe
  stopped at engine.cpp with error C3861: '__builtin_popcount': identifier not found. This was the only MSVC break in the tree.

  It is now a portable Kernighan loop rather than a third per-compiler
  branch: the code runs once per partition at rule setup over a mask of at
  most kMaxNarySlots bits, so there is nothing for an intrinsic to win,
  and MSVC's __popcnt would have carried its own caveats (x86-only, and it
  assumes a POPCNT-capable target).