aspen

tree(1) in wolf: a recursive directory lister whose output is byte-identical to tree 2.3.2's.

The name is the maintainer's pick: in the Yellowstone trophic cascade the wolves' return let the aspens recover. Track 14 of the wolffe-lang org (ruling #102); lanes apNN. Public since 2026-10-21.

What it is

A port of tenseleyFlow/aspen (MIT, the maintainer's), itself written with tree 2.3.2 (GPL-2.0-or-later) as reference; this repository GPL-3.0-or-later (ruling #103).

The C implementation (tenseleyFlow/aspen, pinned in aspen.pin) is read and cited by file:line; the port has no dependency but wolf-std and is built static for PAX, where it is the system's tree.

The oracles

• C aspen at aspen.pin: its golden suite, byte for byte against a tree 2.3.2 on stdout, stderr and exit status, is the oracle of record; where C aspen records a deviation from tree (tests/golden/deviations.sh there), the deviation is the law. The goldens are never edited.
• tree 2.3.2, the distribution's package, run as a black box, the backstop: the same version on kasumi (Arch Linux tree 2.3.2-1), in CI's container, and from Homebrew on macOS. tree's source is never read directly.

In a container of its own (ci/oracle.Containerfile, as a non-root user): tools/golden runs C aspen's golden suite as it is against this binary; tools/oracle runs tree and aspen over generated fixtures (tests/fixtures/mkfixtures) for every invocation in tests/oracle/sets.tsv; tools/fuzz runs C aspen's fuzzer's random trees over its whole flag pool; each prints N agree / M differ / K not-yet. tools/collation measures what the dictionary locale's order changes.

Status

Nothing is released. aspen is byte-identical to tree 2.3.2 and to C aspen, in the C and C.UTF-8 locales, across tree's whole option surface but two (ap00's v1, then ap01): the listing and its filters (-a -d -l -f -x -L -R -P -I --gitignore --gitfile --ignore-case --matchdirs --prune --info --infofile --filelimit --condense --fromfile --fromtabfile --fflinks --noreport --charset -o), the columns (-q -N -Q -p -u -g -s -h --si --du -D --timefmt -F --inodes --device --metafirst), the sorts (-v -t -c -U -r --dirsfirst --filesfirst --sort), the graphics (-i -A -S -n -C --compress, LS_COLORS/TREE_COLORS/CLICOLOR/NO_COLOR), and the formats (-X -J -H -T --nolinks --hintro --houtro --hyperlink --scheme --authority), with --opt-toggle, --help, C aspen's deviations and its own --threads and --asp-diff (two trees compared, tested against C aspen itself: tools/aspdiff). What it does not do, named:

• --acl and --selinux (tree's, on linux) are refused by name, status 2: they read a file's extended attributes, which wolf has no call for;
• names sort by byte in every locale: tree uses the locale's collation, so a dictionary locale such as glibc's en_US.UTF-8 orders some names differently (29 of C aspen's 286 golden cases, every one by order alone: tools/collation); macOS's en_US.UTF-8 collates by byte;
• a name that is not UTF-8 cannot be opened or stat'ed (wolf-lang#687).

Build

The toolchain is fetched by digest (wolf-toolchain.toml): wolf 0.2.35, lupin 0.1.56, wolf-std 2386522e.

tools/fetch-toolchain
tools/build --release              # target/release/aspen
tools/mkaspen target/mkaspen       # static x86-64 Linux, for PAX
tools/check-test                   # the unit tests on three lanes
tools/fetch-c-aspen                # C aspen at aspen.pin, for the oracles
tools/in-container tools/golden    # and the other harnesses, in podman or docker

License

GPL-3.0-or-later (LICENSE), with the org's training-data permission (LICENSE-TRAINING-DATA), as lope has it. aspen is a port of tenseleyFlow/aspen (MIT, the maintainer's), which was itself written with tree 2.3.2 (Steve Baker et al., GPL-2.0-or-later) as reference; tree is also run here as a black-box oracle.