Help Texts

Help text

A short explanation to be displayed as tooltip when the user hovers over a form field, a menu item, or a toolbar button.

Help texts should be (1) helpful to the end user, (2) translated and (3) maintainable. Lino provides several approaches for reaching these goals.

The primitive way

Help texts can be defined and maintained by the application developer by setting the help_text attribute of a field, actor or action. As a developer you should wrap that string into gettext() to have it translatable. Fictive example:

from lino.api import dd, _

class MyModel(dd.Model):
    """MyModel is an important example."""

    universe = models.CharField(_("First field"),
        blank=True, max_length=100, help_text=_("""
The first field contains an optional answer to the
question about life, the universe and everything.
"""))

Help texts can be customized locally per site by the end users as customized help text. This feature is not being used seriously on any known production site.

The help texts extractor

In bigger projects we want to differentiate between application development and authoring of end user documentation. That's why the application developer can delegate help text maintenance to the documentation maintainer.

This is where we use the help texts extractor.

help texts extractor

A Sphinx extension that extracts help texts from your Sphinx documentation to help_texts.py files, which Lino will load at startup.

With the help texts extractor you write the help texts in your documentation using prosa style:

.. class:: MyModel

    MyModel is an important example.

    .. attribute:: universe

        The first field contains an optional answer to the
        question about life, the universe and everything.

        This field is a simple char field. Blabla more documentation.

How it works

When you run inv bd on a Sphinx doctree that has help_texts_extractor installed, Sphinx takes the first paragraph of every object description in your Sphinx documentation and write it to a help_texts.py file.

Note that only the first paragraph of the content of every class and attribute directive is taken as help text, and that any formatting and links are removed.

After having extracted help texts, the application developer can run inv mm and start translating them.

Lino will load these help_texts.py files at startup and "inject" them to the fields, actions and actors as if they had been defined by the application code.

Advantages

  • Better readability, better maintainability.

  • As an application developer you don't need to worry about Python syntax consideration when editing your help text

  • Same source is used for both the docs and the user interface. You don't need to write (and maintain) these texts twice.

The help_texts.py file

help_texts.py

The help_texts.py file contains object descriptions to be installed as the help_text attribute of certain UI widgets: actors, actions and database fields.

It is automatically generated when a full build is being done.

Note that this is done only when all pages of the doctree were built, i.e. when you ran inv clean before running inv bd.

Note that the help texts extractor needs to be configured properly: see the help_texts_builder_targets variable in the conf.py of the book.

When a Lino Site initializes, it looks for a file named help_texts.py in every plugin directory. If such a file exists, Lino imports it and expects it to contain a dict of the form:

from lino.api import _
help_texts = {
    'foo': _("A foo is a bar without baz.")
}

See also

Using help texts

>>> import lino
>>> lino.startup('lino_book.projects.min2.settings.doctests')
>>> from lino.api.doctest import *

Here is how Lino internally accesses the help text of a database field:

>>> fld = rt.models.contacts.Partner._meta.get_field('name')
>>> print(fld.help_text)  
The full name of this partner. Used for alphabetic sorting.

Above text is the first sentence extracted from the documentation of the lino_xl.lib.contacts.Partner.name field.

You can show and test all help texts of a model or actor in functional specifications using the show_fields function:

>>> show_fields(rt.models.contacts.Partner)
+---------------+----------------------------+-----------------------------------------------------------------+
| Internal name | Verbose name               | Help text                                                       |
+===============+============================+=================================================================+
| email         | e-mail address             | The primary email address.                                      |
+---------------+----------------------------+-----------------------------------------------------------------+
| language      | Language                   | The language to use when communicating with this partner.       |
+---------------+----------------------------+-----------------------------------------------------------------+
| phone         | Phone                      | The primary phone number.                                       |
+---------------+----------------------------+-----------------------------------------------------------------+
| gsm           | GSM                        | The primary mobile phone number.                                |
+---------------+----------------------------+-----------------------------------------------------------------+
| city          | Locality                   | The locality, i.e. usually a village, city or town.             |
+---------------+----------------------------+-----------------------------------------------------------------+
| addr1         | Address line before street | Address line before street                                      |
+---------------+----------------------------+-----------------------------------------------------------------+
| street_prefix | Street prefix              | Text to print before name of street, but to ignore for sorting. |
+---------------+----------------------------+-----------------------------------------------------------------+
| street        | Street                     | Name of street, without house number.                           |
+---------------+----------------------------+-----------------------------------------------------------------+
| street_no     | No.                        | House number.                                                   |
+---------------+----------------------------+-----------------------------------------------------------------+
| street_box    | Box                        | Text to print after street number on the same line.             |
+---------------+----------------------------+-----------------------------------------------------------------+
| addr2         | Address line after street  | Address line to print below street line.                        |
+---------------+----------------------------+-----------------------------------------------------------------+
| prefix        | Name prefix                | An optional name prefix. For organisations this is inserted     |
|               |                            | before the name, for persons this is inserted between first     |
|               |                            | name and last name.                                             |
+---------------+----------------------------+-----------------------------------------------------------------+
| name          | Name                       | The full name of this partner. Used for alphabetic sorting.     |
+---------------+----------------------------+-----------------------------------------------------------------+

Don't read on

>>> from lino.api import _
>>> from lino.utils.jsgen import py2js
>>> x = dict(tooltip=_("""This is a "foo", IOW a bar."""))
>>> print(py2js(x))
{ "tooltip": "This is a \"foo\", IOW a bar." }