httk-io

httk-io is the file input/output module for httk₂. It provides:

• the httk.io package within the PEP 420 native httk namespace, currently a CIF/mCIF parser, reader and writer stack; and
• the httk.handlers.io package, which registers the .cif loader with httk-core's plugin registry so files can be read via httk.core.load.

Most users should install the httk2 metapackage, which selects a useful set of httk modules:

pip install httk2

Install only this module (it depends on httk-core and numpy) with:

pip install httk-io

Usage

Importing httk.core discovers httk.handlers.io and registers the .cif loader. httk.core.load then dispatches on the file extension and returns the raw parsed CIF data as a (data_blocks, header) tuple:

import httk.core  # discovery registers the ".cif" loader

data_blocks, header = httk.core.load("structure.cif")
name, block = data_blocks[0]
print(block["cell_length_a"])

Development and release instructions are in the RELEASING.md guide.