yeptris — YAML for Python at libleptris speed
An FFI-based (no C extension) YAML library over libyeptris — the YAML counterpart of libleptris. PyYAML-compatible semantics, one shared library, zero compilation at install.
Install (development)
# the sibling C checkout: ~/src/leptris/yeptris
cmake -B build -S . -DCMAKE_BUILD_TYPE=Release -DYEPTRIS_BUILD_SHARED=ON
cmake --build build
cd ~/src/leptris/yeptris-py
YEPTRIS_LIB_PATH=../yeptris/build/src/libyeptris.dylib python3 -m pytest
Without YEPTRIS_LIB_PATH the loader falls back to a vendored
yeptris/_platform/<tag>/ copy, then to the sibling checkout's
build directory. Any libyeptris.{so,dylib,dll} path works.
Usage
import yeptris
from yeptris import yaml # PyYAML-compatible surface
yaml.safe_load("name: yeptris\nrating: 10\n")
# {'name': 'yeptris', 'rating': 10}
yaml.safe_load_all("--- 1\n--- two\n") # [1, 'two']
yaml.safe_dump({"b": 2, "a": [1, "x"]}) # 'a:\n - 1\n - x\nb: 2\n'
yeptris.load("k: v") # the neutral surface
yeptris.dump({"k": [1, 2]})
Typing follows PyYAML's SafeLoader (YAML 1.1 implicit typing):
yes/no/on/off booleans, 0x/leading-0/0b/sexagesimal integers,
dot-required floats, timestamps with offsets, merge keys, anchor
identity. Every deliberate divergence is pinned by a test.
Design
One parse, one bulk drain: the record array and string arena are
read in two FFI calls, then a pure-Python walk over the unpacked
records — the FFI tax is O(1) per document, never per event (the
same seam yeptris-ruby rides). The 36-byte record layout is
ABI-pinned in the C header and mirrored in _ffi.py.
Performance
python3 bench.py — same-process comparison against PyYAML (pure)
and CSafeLoader/CDumper (libyaml C extensions):
- load: 28-39x PyYAML pure, 3.8-6.1x CSafeLoader
- dump: ~1.7x PyYAML pure, ~2x behind CDumper (which walks the
tree entirely in C — a no-C-extension design's ceiling is the
Python walk itself; the tree raises through ONE
yeptris_document_buildcall)
Both directions are O(chunks) in FFI calls: loads drain records in two calls, dumps build through one flat entry array.
JSON (strict RFC 8259) — yeptris.json
yeptris.json.loads is json.loads-compatible (values, rejects,
types, json.JSONDecodeError — including stdlib's default NaN/
Infinity constant quirk) with two engines behind one contract:
- native — the opt-in extension
ext/yeptris_native.c: a fused scan-kernel descent over libyeptris (the same shape as the Ruby binding's materializer), with a 1024-slot interned-free key cache. Build it withYEPTRIS_LIB_PATH+YEPTRIS_SRCset (python3 setup.py build_ext --inplace); CI builds and gates it. - strict-ffi — the default pure path:
yeptris_parse_jsonis the validator gate, then the columnar value walk converts under JSON rules. No C extension, correct everywhere.
benchmark/json_profile.py is the referee (order-alternating
interleave vs the C scanner): the native engine runs 0.67-0.87x
json.loads mean (83-85% head-to-head) on the 144 KB reference
corpus; shape decomposition: int arrays 0.63x, float arrays 0.77x,
long strings 0.85x, unique-key maps 0.95x. The previous pure walk
was ~15x BEHIND — the fused materializer is the entire gap.
Installing the native JSON engine (platform wheels)
pip install yeptris on macOS (arm64) and manylinux (x86_64)
installs platform wheels that vendor libyeptris and the native
JSON materializer (abi3 — one wheel per platform serves CPython
3.9+): zero compiler, zero env vars, yeptris.json.engine() is
native out of the box. Every wheel is release-smoked in a clean
venv before publish. Other platforms install the pure package (the
strict-ffi JSON engine + YAML via libyeptris through the
YEPTRIS_LIB_PATH ladder); building the extension from source is
YEPTRIS_LIB_PATH=... YEPTRIS_SRC=... python3 setup.py build_ext --inplace.
1 maintainer
Release files for yeptris 0.6.7.3
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| yeptris-0.6.7.3.tar.gz | 26.8 kB | Details |
Built distributions (wheels)
| File | Reset | |||
|---|---|---|---|---|
| yeptris-0.6.7.3-py3-none-any.whl | Python 3 | none | any | Details |
| yeptris-0.6.7.3-cp39-abi3-win_arm64.whl | CPython 3.9 | abi3 | Windows ARM64 | Details |
| yeptris-0.6.7.3-cp39-abi3-win_amd64.whl | CPython 3.9 | abi3 | Windows x86-64 | Details |
| yeptris-0.6.7.3-cp39-abi3-manylinux2014_x86_64.manylinux_2_17_x86_64.whl | CPython 3.9 | abi3 | Linux glibc 2.17+ x86-64 | Details |
| yeptris-0.6.7.3-cp39-abi3-manylinux2014_aarch64.manylinux_2_17_aarch64.whl | CPython 3.9 | abi3 | Linux glibc 2.17+ ARM64 | Details |
| yeptris-0.6.7.3-cp39-abi3-macosx_11_0_x86_64.whl | CPython 3.9 | abi3 | macOS 11.0+ x86-64 | Details |
| yeptris-0.6.7.3-cp39-abi3-macosx_11_0_arm64.whl | CPython 3.9 | abi3 | macOS 11.0+ ARM64 | Details |
Total release size: 1.7 MB
Release files / yeptris-0.6.7.3.tar.gz
| Download URL | yeptris-0.6.7.3.tar.gz |
|---|---|
| Size | 26.8 kB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
0cc303a15450f23069cccbad79417700a8dba6b3765065026836097e18279134
|
|
BLAKE2b-256 checksum How to use checksums |
ecf6328246025edcc46cd66a4389b48780d239810bcb823ae485d6c035ec3335
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-py3-none-any.whl
| Download URL | yeptris-0.6.7.3-py3-none-any.whl |
|---|---|
| Size | 19.3 kB |
| Tags | Python 3 |
|
SHA-256 checksum How to use checksums |
e853d3fd1b88fd97a4d19e1b443f9307c39c587fac044cb8f0e2b43a41404a74
|
|
BLAKE2b-256 checksum How to use checksums |
1316526718db9784ae81a192340578c8b75178cbc0adfd527bb7329b68819efc
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-cp39-abi3-win_arm64.whl
| Download URL | yeptris-0.6.7.3-cp39-abi3-win_arm64.whl |
|---|---|
| Size | 226.6 kB |
| Tags | CPython 3.9 Windows ARM64 abi3 |
|
SHA-256 checksum How to use checksums |
bac89601fb90995cb93fb75ce3ebb4b0f8153b9f975d5c740b08de5147a6955a
|
|
BLAKE2b-256 checksum How to use checksums |
a9e67e7e8d923cbdd63e60a9c5a940fae4429a38557279d04ca8e4d343dff77c
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-cp39-abi3-win_amd64.whl
| Download URL | yeptris-0.6.7.3-cp39-abi3-win_amd64.whl |
|---|---|
| Size | 242.6 kB |
| Tags | CPython 3.9 Windows x86-64 abi3 |
|
SHA-256 checksum How to use checksums |
6b800d6aa2a57ae35c29c073db5b7e61c5939e79a7ca16472c60101df2de43dd
|
|
BLAKE2b-256 checksum How to use checksums |
c1d7a9f472877d3de589caa16924817c872cb23395f4513d915624310485af79
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-cp39-abi3-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
| Download URL | yeptris-0.6.7.3-cp39-abi3-manylinux2014_x86_64.manylinux_2_17_x86_64.whl |
|---|---|
| Size | 315.3 kB |
| Tags | CPython 3.9 Linux glibc 2.17+ x86-64 abi3 |
|
SHA-256 checksum How to use checksums |
c059be47ebcd6d39f32a74e0e711513dc7b79561f3246cc6258ba2ab5df2fe91
|
|
BLAKE2b-256 checksum How to use checksums |
2be2d990a18304b274efafccf184435953a3a756a87d0ff6787e1bf3346ecaca
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-cp39-abi3-manylinux2014_aarch64.manylinux_2_17_aarch64.whl
| Download URL | yeptris-0.6.7.3-cp39-abi3-manylinux2014_aarch64.manylinux_2_17_aarch64.whl |
|---|---|
| Size | 318.8 kB |
| Tags | CPython 3.9 Linux glibc 2.17+ ARM64 abi3 |
|
SHA-256 checksum How to use checksums |
ace29531d3d1a6144308ad983dc1773cf53f2bab06ad77b34fcfa29665a29516
|
|
BLAKE2b-256 checksum How to use checksums |
140ddcfde2a4c44d7ccd2f2e201170ca4a31edf18f402a040bb24c6e8c49e959
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-cp39-abi3-macosx_11_0_x86_64.whl
| Download URL | yeptris-0.6.7.3-cp39-abi3-macosx_11_0_x86_64.whl |
|---|---|
| Size | 280.7 kB |
| Tags | CPython 3.9 abi3 macOS 11.0+ x86-64 |
|
SHA-256 checksum How to use checksums |
4d4e632215e3ac87f29cde7ef38a20119fb0c707f9669f1f2ad44cba0b2e8ac3
|
|
BLAKE2b-256 checksum How to use checksums |
bd5ef8db9801d7854e09d84d258b916508ac9a7d69c3738e212861f1cb750f73
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency logRelease files / yeptris-0.6.7.3-cp39-abi3-macosx_11_0_arm64.whl
| Download URL | yeptris-0.6.7.3-cp39-abi3-macosx_11_0_arm64.whl |
|---|---|
| Size | 267.2 kB |
| Tags | CPython 3.9 abi3 macOS 11.0+ ARM64 |
|
SHA-256 checksum How to use checksums |
f3a453a51a1d566d4e37e2e2addeb7977ff040a841d97a0d15954f42841fdeb2
|
|
BLAKE2b-256 checksum How to use checksums |
e1862975a48894ec54852098c8e6da44aeccebcef8c322f6dda5cae0630f68b1
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 18, 2026.
Transparency log
