Add some documentation

screenplay/src/lib.rs

@@ -10,24 +10,49 @@ Screenplay is distributed in the hope that it will be useful, but WITHOUT ANY WA
 You should have received a copy of the GNU General Public License along with Lumeto. If not, see <https://www.gnu.org/licenses/>.
 */
 
+/// Screenplay is a library that helps visualize GTK scenes. I got my inspiration from working with
+/// Storybook and decided that I wanted a similar tool for GTK.
+///
+/// With this library, you can write an application that loads up a bunch of different user
+/// interfaces, and the library will put them on separate pages. Each UI can have as much or as
+/// little behavior as you want.
 use gtk::prelude::*;
 
 #[derive(Clone, Debug)]
-pub enum Action {
+enum Action {
     SelectPage(usize),
     Deselect,
 }
 
+/// Unused. In the near future, this will contain useful errors.
 #[derive(Clone, Debug)]
 pub struct Error;
 
+/// A definition of a single Screen. The screen can be as much or as little as you want, but must
+/// contain a title (for the page selector) and a widget to show the screen.
 #[derive(Clone)]
 pub struct Screen {
+    /// Title of the screen. This will only be rendered in the page selector.
     pub title: String,
+
+    /// The screen itself. This can be anything that implements the gtk::Widget interface, and it
+    /// will be rendered in the main area of the window.
     pub widget: gtk::Widget,
+
+    /// Unused today, however...
+    /// These will be rendered in an area of the window reserved for adjustments. They are meant to
+    /// be ways to provide variants to the current scene. You will need to attach behaviors.
     pub adjustments: Vec<gtk::Widget>,
 }
 
+/// Screenplay is an object that will render a gtk::ApplicationWindow.
+///
+/// That window contains a sidebar which lists the names of all of the Screens that have been
+/// provided to it. Selecting one of those will cause the application to render that screen and all
+/// of its adjustments.
+///
+/// It is highly likely that in the future this structure will be reformulated as a child of a GTK
+/// ApplicationWindow.
 #[derive(Clone)]
 pub struct Screenplay {
     frame: gtk::Frame,
@@ -35,6 +60,10 @@ pub struct Screenplay {
 }
 
 impl Screenplay {
+    /// Construct a new Screenplay. This will construct and render the ApplicationWindow as the
+    /// primary child of the Application.
+    ///
+    /// This function currently returns no errors, instead panicing if anything goes wrong.
     pub fn new(gtk_app: &gtk::Application, screens: Vec<Screen>) -> Result<Self, Error> {
         let window = gtk::ApplicationWindow::new(gtk_app);
         window.show();
@@ -86,6 +115,7 @@ impl Screenplay {
         Ok(storybook)
     }
 
+    /// Handle an application action. This generally means changing the current screen.
     fn process_action(&mut self, message: Action) -> Continue {
         let nothing: Option<&gtk::Widget> = None;
         match message {