httk.optimade.backend.partial
=============================

.. py:module:: httk.optimade.backend.partial

.. autoapi-nested-parse::

   Markers for property values transmitted via the partial data protocol.

   A field extractor may return a :class:`PartialValue` in place of a concrete
   value when the value is too large to include inline, or when its list axes are
   sliceable. The endpoint layer turns it into ``null`` plus
   ``meta.partial_data_links`` (only the endpoint knows the base URL), slices it
   inline when a ``dimension_slices`` query parameter is supplied, or streams it
   via the JSON Lines partial data endpoint.



Classes
-------

.. autoapisummary::

   httk.optimade.backend.partial.PartialDimension
   httk.optimade.backend.partial.PartialValue


Module Contents
---------------

.. py:class:: PartialDimension

   One list axis of a :class:`PartialValue`.

   ``length`` is the number of items along the axis (``None`` when unknown or
   entry-dependent and not declared). ``sliceable`` indicates whether the
   server can honour a slice request for this axis.


   .. py:attribute:: name
      :type:  str


   .. py:attribute:: length
      :type:  int | None
      :value: None



   .. py:attribute:: sliceable
      :type:  bool
      :value: False



.. py:class:: PartialValue

   A property value provided lazily, one slice at a time.

   ``fetch`` takes a tuple of Python slices (one per dimension, with the usual
   *exclusive* stop) and returns the corresponding nested lists.


   .. py:attribute:: dimensions
      :type:  tuple[PartialDimension, Ellipsis]


   .. py:attribute:: fetch
      :type:  collections.abc.Callable[[tuple[slice, Ellipsis]], Any]