Introduction to actor parameters

Any table in Lino can have optional panel with actor parameters. This document explains what they are. They are both similar and very different from action parameters.

This is a tested document. The following instructions are used for initialization:

>>> from lino import startup
>>> startup('lino_book.projects.apc.settings.doctests')
>>> from lino.api.doctest import *


For example, here is a My Appointments table, first with the parameter panel collapsed and then expanded:

../_images/parameters1.png ../_images/parameters2.png

You can toggle between these two states by clicking the gear button in the toolbar. The help text of that button says Show or hide the table parameters. This button is available only on tables that do have parameters.

actor parameter

A run-time parameter that can be given to an actor in the parameter panel.

Actor parameters are stored in the parameters attribute of their Actor.

parameter panel

A panel used to enter actor parameters of an actor. In ExtJS it expands or collapses by clicking the gear button in the toolbar.

simple actor parameter

An actor parameter that maps to a given database field. For example lino_xl.lib.contacts.Persons.gender is a simple actor parameter that, when set, will cause the table to show only persons of the gender given in the parameter panel. You declare them by overriding the get_simple_parameters method of your model.

>>> pprint(rt.models.contacts.Persons.parameters)
{'aged_from': <django.db.models.fields.IntegerField: aged_from>,
 'aged_to': <django.db.models.fields.IntegerField: aged_to>,
 'end_date': <django.db.models.fields.DateField: end_date>,
 'gender': <lino.core.choicelists.ChoiceListField: gender>,
 'observed_event': <lino.core.choicelists.ChoiceListField: observed_event>,
 'start_date': <django.db.models.fields.DateField: start_date>}

Only one of these is a simple parameter:

>>> list(rt.models.contacts.Persons.get_simple_parameters())

For the other parameters we must override the model's lino.core.model.Model.get_request_queryset() method in order to tell Lino how they influence the data to be displayed.

TODO: continue to write documentation.