tranche

ConfigParser with layered precedence, provenance, comment-preserving writes, and safe expressions.

The name tranche comes from the French word for slice — a nod to how the library lets you cut cleanly through multiple configuration layers to get a single, effective view of your settings.

Documentation

Full docs: https://xylar.github.io/tranche/

Install

• From PyPI (no NumPy):

pip install tranche

• With NumPy extras (to enable safe NumPy expressions):

pip install tranche[numpy]

• From source (local checkout):

pip install .

Quick start

from tranche import Tranche

config = Tranche()
config.add_from_file("defaults.cfg")
config.add_user_config("user.cfg")

# Simple values
value = config.get("core", "option")

# Expression (literal backend chosen automatically)
points = config.getexpression("plot", "ticks")

# NumPy expression (auto-selects safe backend because allow_numpy=True)
arr = config.getexpression("plot", "bins", allow_numpy=True)

# Or via convenience helper
arr2 = config.getnumpy("plot", "bins")

# Provenance
info = config.explain("plot", "bins")
print(info)

Security notes

• Expressions default to backend="literal" for safety.
• The safe backend only allows a small AST subset and a very small set of symbols.
• NumPy is opt-in via allow_numpy=True and the numpy extra.

Extensibility

You can add your own safe symbols:

import math
config.register_symbol("sqrt", math.sqrt)

Links

• Docs: https://xylar.github.io/tranche/
• Source: https://github.com/xylar/tranche
• Issues: https://github.com/xylar/tranche/issues

License

BSD-3-Clause