--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/book/en/04-develop-views.en.txt	Fri Nov 14 11:05:32 2008 +0100
@@ -0,0 +1,126 @@
+.. -*- coding: utf-8 -*-
+
+
+Developing the user interface with Views
+========================================
+
+Before moving to this section, make sure you read the `Essentials`
+section in the Introduction.
+
+Tip: when modifying views, you do not need to restart the local 
+server. Just save the file in your editor and reload the page in your
+browser to see the changes.
+
+The selection/view principle
+----------------------------
+
+With `LAX`, views are defined by Python classes. A view includes :
+
+- an identifier (all objects in `LAX` are entered in a registry
+  and this identifier will be used as a key)
+  
+- a filter to select the resulsets it can be applied to
+
+`LAX` provides a lot of standard views, for a complete list, you
+will have to read the code in directory ``ginco/web/views/`` (XXX
+improve doc).
+
+For example, the view named ``primary`` is the one used to display
+a single entity.
+
+If you want to change the way a ``BlogEntry`` is displayed, just
+override the view ``primary`` in ``BlogDemo/views.py`` ::
+
+  01. from ginco.web.views import baseviews
+  02.
+  03. class BlogEntryPrimaryView(baseviews.PrimaryView):
+  04.
+  05.     accepts = ('BlogEntry',)
+  06.
+  07.     def cell_call(self, row, col):
+  08.         entity = self.entity(row, col)
+  09.         self.w(u'<h1>%s</h1>' % entity.title)
+  10.         self.w(u'<p>published on %s in category %s</p>' % \
+  11.                (entity.publish_date.strftime('%Y-%m-%d'), entity.category))
+  12.         self.w(u'<p>%s</p>' % entity.text)
+
+The above source code defines a new primary view (`line 03`) for
+``BlogEntry`` (`line 05`). 
+
+Since views are applied to resultsets and resulsets can be tables of
+data, it is needed to recover the entity from its (row,col)
+coordinates (`line 08`). We will get to this in more detail later.
+
+The view has a ``self.w()`` method that is used to output data. Here `lines
+09-12` output HTML tags and values of the entity's attributes.
+
+When displaying same blog entry as before, you will notice that the
+page is now looking much nicer.
+
+.. image:: images/lax-book.09-new-view-blogentry.en.png
+   :alt: blog entries now look much nicer
+
+Let us now improve the primary view of a blog ::
+
+  01. class BlogPrimaryView(baseviews.PrimaryView):
+  02. 
+  03.     accepts = ('Blog',)
+  04.
+  05.     def cell_call(self, row, col):
+  06.         entity = self.entity(row, col)
+  07.         self.w(u'<h1>%s</h1>' % entity.title)
+  08.         self.w(u'<p>%s</p>' % entity.description)
+  09.         rset = self.req.execute('Any E WHERE E entry_of B, B eid "%s"' % entity.eid)
+  10.         self.wview('primary', rset)
+
+In the above source code, `lines 01-08` are similar to the previous
+view we defined.
+
+At `line 09`, a simple request in made to build a resultset with all
+the entities linked to the current ``Blog`` entity by the relationship
+``entry_of``. The part of the framework handling the request knows
+about the schema and infer that such entities have to be of the
+``BlogEntry`` kind and retrieves them.
+
+The request returns a selection of data called a resultset. At 
+`line 10` the view 'primary' is applied to this resultset to output
+HTML. 
+
+**This is to be compared to interfaces and protocols in object-oriented
+languages. Applying a given view to all the entities of a resultset only
+requires the availability, for each entity of this resultset, of a
+view with that name that can accepts the entity.**
+
+Assuming we added entries to the blog titled `MyLife`, displaying it
+now allows to read its description and all its entries.
+
+.. image:: images/lax-book.10-blog-with-two-entries.en.png
+   :alt: a blog and all its entries
+
+**Before we move forward, remember that the selection/view principle is
+at the core of `LAX`. Everywhere in the engine, data is requested
+using the RQL language, then HTML/XML/text/PNG is output by applying a
+view to the resultset returned by the query. That is where most of the
+flexibility comes from.**
+
+[WRITE ME]
+
+* implementing interfaces, calendar for blog entries
+* show that a calendar view can export data to ical
+
+We will implement the ginco.interfaces.ICalendarable interfaces on
+entities.BloEntry and apply the OneMonthCalendar and iCalendar views
+to resultsets like "Any E WHERE E is BlogEntry"
+
+* create view "blogentry table" with title, publish_date, category
+
+We will show that by default the view that displays 
+"Any E,D,C WHERE E publish_date D, E category C" is the table view.
+Of course, the same can be obtained by calling
+self.wview('table',rset)
+
+* in view blog, select blogentries and apply view "blogentry table"
+* demo ajax by filtering blogentry table on category
+
+we did the same with 'primary', but with tables we can turn on filters
+and show that ajax comes for free.