added an example to chapter 14 about Grid + checkboxes

docs/chapter-06.rst

@@ -156,6 +156,7 @@ templates. Here is a simple example:
 
 .. code:: python
 
+   from py4web.utils.factories import Inject
    my_var = "Example variable to be passed to a Template"
 
    ...
@@ -213,6 +214,28 @@ action with a counter that counts “visits”.
        session['counter'] = counter
        return str(T("You have been here {n} times").format(n=counter))
 
+
+If the `T` fixture is to be used from inside a template you may want to pass it to the template:
+
+.. code:: python
+
+   @action('index')
+   @action.uses("index.html", session, T)
+   def index():
+       return dict(T=T)
+
+Or perahps inject (same effect as above)
+
+.. code:: python
+
+   from py4web.utils.factories import Inject
+
+   @action('index')
+   @action.uses("index.html", session, Inject(T=T)
+   def index():
+       return dict()
+
+
 Now create the following translation file ``translations/en.json``:
 
 .. code:: json
@@ -258,6 +281,31 @@ Now try create a file called ``translations/it.json`` which contains:
 Set your browser preference to Italian: now the messages will be
 automatically translated to Italian.
 
+Notice there is UI for creating, updating, and updating translation files.
+The UI is accessing via a button from the Dashboard.
+
+If you want to force an action to use language defined somewhere else, for example from a session variable, you can do:
+
+.. code:: python
+
+   @action('index')
+   @action.uses("index.html", session, T)
+   def index():
+       T.select(session.get("lang", "it"))
+       return dict(T=T)
+
+If you want all of your action to use the same pre-defined language and ignore browser preferences,
+you have to redefine the select method for the T instance:
+
+.. code:: python
+
+   T.on_request = lambda *_: T.local.__dict__.update(tag="it", language=T.languages["it"])
+
+This is to be done outside any action and will apply to all actions. Action will still need todeclare 
+`action.uses(T)` else the behavior is undefined.
+
+
+
 The Flash fixture
 -----------------
 

docs/chapter-14.rst

@@ -584,3 +584,39 @@ combine fields to be displayed together as the filter_out method would
 You need to determine which method is best for your use case
 understanding the different grids in the same application may need to
 behave differently.
+
+
+Grids with checkboxes
+---------------------
+
+While the grid, per se, does not support checkboxes, you can use custom columns to add one or more columns of checboxes.
+You can also add the helpers logic (the grid uses helpers to generate HTML) to wrap it in a ``<form>`` and add one 
+or more submit bottons. You can then add logic to process the selected rows when the button is selected. For example:
+
+.. code:: python
+
+   column = Column("select", lambda row: INPUT(_type="checkbox",_name="selected_id",_value=row.id))
+
+   @action("manage")
+   @action("manage/<path:path>")
+   @action.uses("manage.html", db)
+   def manage(path=None):
+
+      grid = Grid(path, db.thing, columns=[column, db.thing.name])
+
+      # if we are displaying a "select" grid page (not a form)
+      if not grid.form:
+         grid = grid.render()
+         # if checkboxes selection was submitted
+         if request.method == "POST":
+            # do something with the selected ids
+            print("you selected", request.POST.get("selected_id"))
+         # inject a ``<form>`` and a ``submit`` button
+         grid.children[1:] = [FORM(
+               *grid.children[1:],
+               DIV(INPUT(_type="submit",_value="do it!")),
+               _method="POST",
+               _action=request.url)]        
+      return locals()
+
+Notice in the above example ``request.POST.get("selected_id")`` can be a single ID (if one selected) or a list of IDs (if more than one elsected).