v0.6.0

Added

• SpecSelectorView: a selector spec served as a page to read. It
  answers GET and HEAD, admits the request as every page does, reads the
  query string as the spec's arguments and runs dispatch. A LIST spec is a
  list page, a RETRIEVE spec one row's page, and a row the selector does not
  find is Http404. The template is handed the selector's own rows, as
  rows and, on an instance page, row; the shipped spec_selector.html
  shows each as its Output marks it, so as_view() refuses a spec whose
  Output it cannot display unless table_class is set or
  display_rows = False.
  • Paging by the kernel's paginate_output, one COUNT and the page:
    page_kwarg, paginate_by, max_page_size, and an opt-in
    page_size_kwarg a client chooses the size with, bounded by
    max_page_size. The paging keys are taken off the query before the spec
    reads it, so ?page=2 is never refused as an undeclared argument, and
    as_view() refuses a list spec declaring a parameter under a paging key.
    A page or size that is not a whole number is the default; the context's
    page, previous_page_query and next_page_query keep every filter.
  • Filters: the spec's filter_set, as filter, bound to the query for
    display and never validated by the page. Dispatch's refusal is placed on
    its form, and the page renders at the refusal's status with every
    message in errors; an htmx request is answered with the results alone,
    a refusal at 200.
  • django-tables2, composed and never imported. table_class builds a
    host's Table over the page's rows with no request and order_by=(),
    so the table never pages or reorders what the spec returned.
    table_order_by_field names the spec's own ordering parameter for the
    header links, and as_view() refuses one the spec does not declare.
• The available template filter, {% load django_spec_html %} and
  {% if row|available:"withdraw" %}. It reads the answers the page
  attached to each row it served, from the flags dispatch annotated on the
  page's one query, so asking costs no query and a page costs the same
  number of queries for three rows as for thirty. A name the row's spec does
  not declare raises TemplateSyntaxError, naming those it does.
• docs/selectors.md and a runnable example, docs/examples/spec_selector.py:
  a list page, a table page with a column asking each row what it offers, an
  instance page and the confirmation page a row links to.

Changed

• A query string and a form are read by the kernel's flat_arguments.
  request_arguments reads one through the kernel's reader rather than this
  package's own copy of it, with the same rules: the comma split for typed
  arrays, a blank as absent unless "" is a value the parameter takes, an
  array read no further than one past its cap, and the CSRF field dropped.
• Requires django-service-specs>=0.20.0, the release carrying that
  reader; the list pages need 0.19.0's row_affordance_answers.

Fixed

• A changelist action's selection is read by the same flat rules. The
  admin page read its selected keys with getlist alone, so ?pks=1,2 was
  one key the parameter refused rather than two, and a blank selection was a
  malformed key rather than none.