update firstapp chapter

1 files changed, 149 insertions, 155 deletions

diff --git a/docs/narr/firstapp.rst b/docs/narr/firstapp.rst
index 419bc41e5..8f166a403 100644
--- a/docs/narr/firstapp.rst
+++ b/docs/narr/firstapp.rst
@@ -3,25 +3,24 @@
 Creating Your First :app:`Pyramid` Application
 =================================================
 
-We will walk through the creation of a tiny :app:`Pyramid`
-application in this chapter.  After we're finished creating it, we'll
-explain in more detail how the application works.
+In this chapter, we will walk through the creation of a tiny :app:`Pyramid`
+application.  After we're finished creating the application, we'll explain in
+more detail how it works.
 
 .. note::
 
    If you're a "theory-first" kind of person, you might choose to read
-   :ref:`contextfinding_chapter` and :ref:`views_chapter` to augment
-   your understanding before diving into the code that follows, but
-   it's not necessary if -- like many programmers -- you're willing to
-   "go with the flow".
+   :ref:`contextfinding_chapter` and :ref:`views_chapter` before diving into
+   the code that follows, but it's not necessary if -- like many programmers
+   -- you're willing to "go with the flow".
 
 .. _helloworld_imperative:
 
 Hello World, Goodbye World
 --------------------------
 
-Here's one of the very simplest :app:`Pyramid` applications,
-configured imperatively:
+Here's one of the very simplest :app:`Pyramid` applications, configured
+imperatively:
 
 .. code-block:: python
    :linenos:
@@ -52,18 +51,18 @@ installed, an HTTP server is started on TCP port 8080:
    $ python helloworld.py
    serving on 0.0.0.0:8080 view at http://127.0.0.1:8080
 
-When port 8080 is visited by a browser on the root URL
-(``/``), the server will simply serve up the text "Hello world!"  When
-visited by a browser on the URL ``/goodbye``, the server will serve up
-the text "Goodbye world!"
- 
-Now that we have a rudimentary understanding of what the application
-does, let's examine it piece-by-piece.
+When port 8080 is visited by a browser on the root URL (``/``), the server
+will simply serve up the text "Hello world!"  When visited by a browser on
+the URL ``/goodbye``, the server will serve up the text "Goodbye world!"
+
+Now that we have a rudimentary understanding of what the application does,
+let's examine it piece-by-piece.
 
 Imports
 ~~~~~~~
 
-The above script defines the following set of imports:
+The above ``helloworld.py`` script uses the following set of import
+statements:
 
 .. code-block:: python
    :linenos:
@@ -72,11 +71,10 @@ The above script defines the following set of imports:
    from pyramid.response import Response
    from paste.httpserver import serve
 
-The script imports the ``Configurator`` class from the
-``pyramid.config`` module.  This class is used to configure
-:app:`Pyramid` for a particular application.  An instance of this class
-provides methods which help configure various parts of :app:`Pyramid` for a
-given application deployment.
+The script imports the :class:`~pyramid.config.Configurator` class from the
+:mod:`pyramid.config` module.  An instance of the
+:class:`~pyramid.config.Configurator` class is later used to configure your
+:app:`Pyramid` application.
 
 The script uses the :class:`pyramid.response.Response` class later in the
 script to create a :term:`response` object.
@@ -84,13 +82,14 @@ script to create a :term:`response` object.
 Like many other Python web frameworks, :app:`Pyramid` uses the :term:`WSGI`
 protocol to connect an application and a web server together.  The
 :mod:`paste.httpserver` server is used in this example as a WSGI server for
-convenience, as the ``paste`` package is a dependency of :app:`Pyramid` itself.
+convenience, as the ``paste`` package is a dependency of :app:`Pyramid`
+itself.
 
 View Callable Declarations
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The above script, beneath its set of imports, defines two functions:
-one named ``hello_world`` and one named ``goodbye_world``.
+The above script, beneath its set of imports, defines two functions: one
+named ``hello_world`` and one named ``goodbye_world``.
 
 .. code-block:: python
    :linenos:
@@ -101,22 +100,21 @@ one named ``hello_world`` and one named ``goodbye_world``.
    def goodbye_world(request):
        return Response('Goodbye world!')
 
-These functions don't do anything very taxing.  Both functions accept
-a single argument (``request``).  The ``hello_world`` function does
-nothing but return a response instance with the body ``Hello world!``.
-The ``goodbye_world`` function returns a response instance with the
-body ``Goodbye world!``.
+These functions don't do anything very difficult.  Both functions accept a
+single argument (``request``).  The ``hello_world`` function does nothing but
+return a response instance with the body ``Hello world!``.  The
+``goodbye_world`` function returns a response instance with the body
+``Goodbye world!``.
 
-Each of these functions is known as a :term:`view callable`.  View
-callables in a :app:`Pyramid` application accept a single argument,
-``request`` and are expected to return a :term:`response` object.  A
-view callable doesn't need to be a function; it can be represented via
-another type of object, like a class or an instance, but for our
-purposes here, a function serves us well.
+Each of these functions is known as a :term:`view callable`.  A view callable
+accepts a single argument, ``request``.  It is expected to return a
+:term:`response` object.  A view callable doesn't need to be a function; it
+can be represented via another type of object, like a class or an instance,
+but for our purposes here, a function serves us well.
 
-A view callable is always called with a :term:`request` object.  A
-request object is a representation of an HTTP request sent to
-:app:`Pyramid` via the active :term:`WSGI` server.
+A view callable is always called with a :term:`request` object.  A request
+object is a representation of an HTTP request sent to :app:`Pyramid` via the
+active :term:`WSGI` server.
 
 A view callable is required to return a :term:`response` object because a
 response object has all the information necessary to formulate an actual HTTP
@@ -127,6 +125,12 @@ class.  In the ``hello_world`` function, the string ``'Hello world!'`` is
 passed to the ``Response`` constructor as the *body* of the response.  In the
 ``goodbye_world`` function, the string ``'Goodbye world!'`` is passed.
 
+.. note:: As we'll see in later chapters, returning a literal
+   :term:`response` object from a view callable is not always required; we
+   can instead use a :term:`renderer` in our view configurations.  If we use
+   a renderer, our view callable is allowed to return a value that the
+   renderer understands, and the renderer generates a response on our behalf.
+
 .. index::
    single: imperative configuration
    single: Configurator
@@ -137,10 +141,10 @@ passed to the ``Response`` constructor as the *body* of the response.  In the
 Application Configuration
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
-In the above script, the following code represents the *configuration* of this
-simple application. The application is configured using the previously defined
-imports and function definitions, placed within the confines of an ``if``
-statement:
+In the above script, the following code represents the *configuration* of
+this simple application. The application is configured using the previously
+defined imports and function definitions, placed within the confines of an
+``if`` statement:
 
 .. code-block:: python
    :linenos:
@@ -163,28 +167,26 @@ Configurator Construction
    if __name__ == '__main__':
        config = Configurator()
 
-The ``if __name__ == '__main__':`` line in the code sample above
-represents a Python idiom: the code inside this if clause is not
-invoked unless the script containing this code is run directly from
-the command line. For example, if the file named ``helloworld.py``
-contains the entire script body, the code within the ``if`` statement
-will only be invoked when ``python helloworld.py`` is executed from
-the operating system command line.
-
-``helloworld.py`` in this case is a Python *module*.  Using the ``if``
-clause is necessary -- or at least best practice -- because code in
-any Python module may be imported by another Python module.  By using
-this idiom, the script is indicating that it does not want the code
-within the ``if`` statement to execute if this module is imported; the
-code within the ``if`` block should only be run during a direct script
-execution.
+The ``if __name__ == '__main__':`` line in the code sample above represents a
+Python idiom: the code inside this if clause is not invoked unless the script
+containing this code is run directly from the command line. For example, if
+the file named ``helloworld.py`` contains the entire script body, the code
+within the ``if`` statement will only be invoked when ``python
+helloworld.py`` is executed from the operating system command line.
+
+``helloworld.py`` in this case is a Python :term:`module`.  Using the ``if``
+clause is necessary -- or at least best practice -- because code in any
+Python module may be imported by another Python module.  By using this idiom,
+the script is indicating that it does not want the code within the ``if``
+statement to execute if this module is imported; the code within the ``if``
+block should only be run during a direct script execution.
 
 The ``config = Configurator()`` line above creates an instance of the
-:class:`pyramid.config.Configurator` class.  The resulting
-``config`` object represents an API which the script uses to configure
-this particular :app:`Pyramid` application.  Methods called on the
-Configurator will cause registrations to be made in a
-:term:`application registry` associated with the application.
+:class:`~pyramid.config.Configurator` class.  The resulting ``config`` object
+represents an API which the script uses to configure this particular
+:app:`Pyramid` application.  Methods called on the Configurator will cause
+registrations to be made in a :term:`application registry` associated with
+the application.
 
 .. _adding_configuration:
 
@@ -198,61 +200,55 @@ Adding Configuration
    config.add_view(hello_world)
    config.add_view(goodbye_world, name='goodbye')
 
-Each of these lines calls the
-:meth:`pyramid.config.Configurator.add_view` method.  The
-``add_view`` method of a configurator registers a :term:`view
+Each of these lines calls the :meth:`pyramid.config.Configurator.add_view`
+method.  The ``add_view`` method of a configurator registers a :term:`view
 configuration` within the :term:`application registry`.  A :term:`view
 configuration` represents a set of circumstances related to the
 :term:`request` that will cause a specific :term:`view callable` to be
-invoked.  This "set of circumstances" is provided as one or more
-keyword arguments to the ``add_view`` method.  Each of these keyword
-arguments is known as a view configuration :term:`predicate`.
-
-The line ``config.add_view(hello_world)`` registers the
-``hello_world`` function as a view callable.  The ``add_view`` method
-of a Configurator must be called with a view callable object or a
-:term:`dotted Python name` as its first argument, so the first
-argument passed is the ``hello_world`` function.  This line calls
-``add_view`` with a *default* value for the :term:`predicate`
+invoked.  This "set of circumstances" is provided as one or more keyword
+arguments to the ``add_view`` method.  Each of these keyword arguments is
+known as a view configuration :term:`predicate`.
+
+The line ``config.add_view(hello_world)`` registers the ``hello_world``
+function as a view callable.  The ``add_view`` method of a Configurator must
+be called with a view callable object or a :term:`dotted Python name` as its
+first argument, so the first argument passed is the ``hello_world`` function.
+This line calls ``add_view`` with a *default* value for the :term:`predicate`
 argument, named ``name``.  The ``name`` predicate defaults to a value
-equalling the empty string (``''``).  This means that we're
-instructing :app:`Pyramid` to invoke the ``hello_world`` view
-callable when the :term:`view name` is the empty string.  We'll learn
-in later chapters what a :term:`view name` is, and under which
-circumstances a request will have a view name that is the empty
-string; in this particular application, it means that the
-``hello_world`` view callable will be invoked when the root URL ``/``
-is visited by a browser.
-
-The line ``config.add_view(goodbye_world, name='goodbye')`` registers
-the ``goodbye_world`` function as a view callable.  The line calls
-``add_view`` with the view callable as the first required positional
-argument, and a :term:`predicate` keyword argument ``name`` with the
-value ``'goodbye'``.  The ``name`` argument supplied in this
-:term:`view configuration` implies that only a request that has a
-:term:`view name` of ``goodbye`` should cause the ``goodbye_world``
-view callable to be invoked.  In this particular application, this
-means that the ``goodbye_world`` view callable will be invoked when
-the URL ``/goodbye`` is visited by a browser.
-
-Each invocation of the ``add_view`` method implies a :term:`view
-configuration` registration.  Each :term:`predicate` provided as a
-keyword argument to the ``add_view`` method narrows the set of
-circumstances which would cause the view configuration's callable to
-be invoked.  In general, a greater number of predicates supplied along
-with a view configuration will more strictly limit the applicability
-of its associated view callable.  When :app:`Pyramid` processes a
-request, the view callable with the *most specific* view
-configuration (the view configuration that matches the most specific
-set of predicates) is always invoked.
-
-In this application, :app:`Pyramid` chooses the most specific view
-callable based only on view :term:`predicate` applicability.  The
-ordering of calls to
-:meth:`pyramid.config.Configurator.add_view` is never very
-important.  We can register ``goodbye_world`` first and
-``hello_world`` second; :app:`Pyramid` will still give us the most
-specific callable when a request is dispatched to it.
+equalling the empty string (``''``).  This means that we're instructing
+:app:`Pyramid` to invoke the ``hello_world`` view callable when the
+:term:`view name` is the empty string.  We'll learn in later chapters what a
+:term:`view name` is, and under which circumstances a request will have a
+view name that is the empty string; in this particular application, it means
+that the ``hello_world`` view callable will be invoked when the root URL
+``/`` is visited by a browser.
+
+The line ``config.add_view(goodbye_world, name='goodbye')`` registers the
+``goodbye_world`` function as a view callable.  The line calls ``add_view``
+with the view callable as the first required positional argument, and a
+:term:`predicate` keyword argument ``name`` with the value ``'goodbye'``.
+The ``name`` argument supplied in this :term:`view configuration` implies
+that only a request that has a :term:`view name` of ``goodbye`` should cause
+the ``goodbye_world`` view callable to be invoked.  In this particular
+application, this means that the ``goodbye_world`` view callable will be
+invoked when the URL ``/goodbye`` is visited by a browser.
+
+Each invocation of the ``add_view`` method registers a :term:`view
+configuration`.  Each :term:`predicate` provided as a keyword argument to the
+``add_view`` method narrows the set of circumstances which would cause the
+view configuration's callable to be invoked.  In general, a greater number of
+predicates supplied along with a view configuration will more strictly limit
+the applicability of its associated view callable.  When :app:`Pyramid`
+processes a request, the view callable with the *most specific* view
+configuration (the view configuration that matches the most specific set of
+predicates) is always invoked.
+
+In this application, :app:`Pyramid` chooses the most specific view callable
+based only on view :term:`predicate` applicability.  The ordering of calls to
+:meth:`pyramid.config.Configurator.add_view` is never very important.  We can
+register ``goodbye_world`` first and ``hello_world`` second; :app:`Pyramid`
+will still give us the most specific callable when a request is dispatched to
+it.
 
 .. index::
    single: make_wsgi_app
@@ -267,28 +263,26 @@ WSGI Application Creation
 
    app = config.make_wsgi_app()
 
-After configuring views and ending configuration, the script creates a
-WSGI *application* via the
-:meth:`pyramid.config.Configurator.make_wsgi_app` method.  A
-call to ``make_wsgi_app`` implies that all configuration is finished
-(meaning all method calls to the configurator which set up views, and
-various other configuration settings have been performed).  The
-``make_wsgi_app`` method returns a :term:`WSGI` application object
-that can be used by any WSGI server to present an application to a
-requestor.  :term:`WSGI` is a protocol that allows servers to talk to
-Python applications.  We don't discuss :term:`WSGI` in any depth
-within this book, however, you can learn more about it by visiting
-`wsgi.org <http://wsgi.org>`_.
-
-The :app:`Pyramid` application object, in particular, is an
-instance of a class representing a :app:`Pyramid` :term:`router`.
-It has a reference to the :term:`application registry` which resulted
-from method calls to the configurator used to configure it.  The
-:term:`router` consults the registry to obey the policy choices made
-by a single application.  These policy choices were informed by method
-calls to the :term:`Configurator` made earlier; in our case, the only
-policy choices made were implied by two calls to its ``add_view``
-method.
+After configuring views and ending configuration, the script creates a WSGI
+*application* via the :meth:`pyramid.config.Configurator.make_wsgi_app`
+method.  A call to ``make_wsgi_app`` implies that all configuration is
+finished (meaning all method calls to the configurator which set up views,
+and various other configuration settings have been performed).  The
+``make_wsgi_app`` method returns a :term:`WSGI` application object that can
+be used by any WSGI server to present an application to a requestor.
+:term:`WSGI` is a protocol that allows servers to talk to Python
+applications.  We don't discuss :term:`WSGI` in any depth within this book,
+however, you can learn more about it by visiting `wsgi.org
+<http://wsgi.org>`_.
+
+The :app:`Pyramid` application object, in particular, is an instance of a
+class representing a :app:`Pyramid` :term:`router`.  It has a reference to
+the :term:`application registry` which resulted from method calls to the
+configurator used to configure it.  The :term:`router` consults the registry
+to obey the policy choices made by a single application.  These policy
+choices were informed by method calls to the :term:`Configurator` made
+earlier; in our case, the only policy choices made were implied by two calls
+to its ``add_view`` method.
 
 WSGI Application Serving
 ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -299,34 +293,34 @@ WSGI Application Serving
 
    serve(app, host='0.0.0.0')
 
-Finally, we actually serve the application to requestors by starting
-up a WSGI server.  We happen to use the :func:`paste.httpserver.serve`
-WSGI server runner, passing it the ``app`` object (a :term:`router`)
-as the application we wish to serve.  We also pass in an argument
-``host=='0.0.0.0'``, meaning "listen on all TCP interfaces."  By
-default, the Paste HTTP server listens only on the ``127.0.0.1``
-interface, which is problematic if you're running the server on a
-remote system and you wish to access it with a web browser from a
-local system.  We don't specify a TCP port number to listen on; this
+Finally, we actually serve the application to requestors by starting up a
+WSGI server.  We happen to use the :func:`paste.httpserver.serve` WSGI server
+runner, passing it the ``app`` object (a :term:`router`) as the application
+we wish to serve.  We also pass in an argument ``host=='0.0.0.0'``, meaning
+"listen on all TCP interfaces."  By default, the Paste HTTP server listens
+only on the ``127.0.0.1`` interface, which is problematic if you're running
+the server on a remote system and you wish to access it with a web browser
+from a local system.  We don't specify a TCP port number to listen on; this
 means we want to use the default TCP port, which is 8080.
 
-When this line is invoked, it causes the server to start listening on
-TCP port 8080.  It will serve requests forever, or at least until we
-stop it by killing the process which runs it.
+When this line is invoked, it causes the server to start listening on TCP
+port 8080.  It will serve requests forever, or at least until we stop it by
+killing the process which runs it (usually by pressing ``Ctrl-C`` in the
+terminal we used to start it).
 
 Conclusion
 ~~~~~~~~~~
 
-Our hello world application is one of the simplest possible
-:app:`Pyramid` applications, configured "imperatively".  We can see
-that it's configured imperatively because the full power of Python is
-available to us as we perform configuration tasks.
+Our hello world application is one of the simplest possible :app:`Pyramid`
+applications, configured "imperatively".  We can see that it's configured
+imperatively because the full power of Python is available to us as we
+perform configuration tasks.
 
 .. note::
 
-  An example of using *declarative* configuration (:term:`ZCML`) instead of
-  imperative configuration to create a similar "hello world" is available
-  within :ref:`declarative_configuration`.
+   An example of using *declarative* configuration (:term:`ZCML`) instead of
+   imperative configuration to create a similar "hello world" is available
+   within :ref:`declarative_configuration`.
 
 References
 ----------