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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 to and different from action parameters.

Lines starting with >>> in this document are code snippets that get tested as part of our development workflow.

>>> from lino import startup
>>> startup('lino_book.projects.apc.settings')
>>> 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.

  • lino.core.utils.Parametrizable.parameters

class lino.core.model.Model
class lino.core.actors.Actor

User-definable parameter fields for this actor or action. Set this to a dict of name = models.XyzField() pairs.

params_layout = None

The layout to be used for the parameter panel. If this table or action has parameters, specify here how they should be laid out in the parameters panel.

params_panel_hidden = True

If this table has parameters, set this to True if the parameters panel should be initially hidden when this table is being displayed.


Where to place the parameters panel within the list window when it is expanded. Allowed values are “top”, “bottom”, “left” and “right”

use_detail_param_panel = False

Set to true if you want the params panel to be displayed in the detail view. Used only in lino_xl.lib.cal.CalView.

simple_parameters = None

A tuple of names of filter parameters that are handled automatically.

Application developers should not set this attribute directly, they should rather define a get_simple_parameters() on the model.


Hook for defining which parameters are simple.

Expected to return a list of names of parameter fields.