Make some fixes and update to documentation

crates/fj-math/src/line.rs

@@ -79,7 +79,7 @@ impl<const D: usize> Line<D> {
     /// Access the direction of the line
     ///
     /// The length of this vector defines the unit of the line's curve
-    /// coordinate system. The coordinate `1.` is always were the direction
+    /// coordinate system. The coordinate `1.` is always where the direction
     /// vector points, from `origin`.
     pub fn direction(&self) -> Vector<D> {
         self.direction

crates/fj-window/src/display.rs

@@ -121,7 +121,7 @@ pub fn display(model: Model, invert_zoom: bool) -> Result<(), Error> {
 pub enum Error {
     /// Error initializing window
     #[error("Error initializing window")]
-    WindowInit(#[from] window::Error),
+    WindowInit(#[from] window::WindowError),
 
     /// Error initializing graphics
     #[error("Error initializing graphics")]

crates/fj-window/src/lib.rs

@@ -13,4 +13,7 @@
 mod display;
 mod window;
 
-pub use self::display::{display, Error};
+pub use self::{
+    display::{display, Error},
+    window::WindowError,
+};

crates/fj-window/src/window.rs

@@ -6,7 +6,7 @@ pub struct Window(winit::window::Window);
 
 impl Window {
     /// Create an instance of `Window` from the given `EventLoop`
-    pub fn new<T>(event_loop: &EventLoop<T>) -> Result<Self, Error> {
+    pub fn new<T>(event_loop: &EventLoop<T>) -> Result<Self, WindowError> {
         let window = WindowBuilder::new()
             .with_title("Fornjot")
             .with_maximized(true)
@@ -57,4 +57,4 @@ impl Screen for Window {
 /// Error initializing window
 #[derive(Debug, thiserror::Error)]
 #[error("Error initializing window")]
-pub struct Error(#[from] pub winit::error::OsError);
+pub struct WindowError(#[from] pub winit::error::OsError);

crates/fj/src/args.rs

@@ -4,6 +4,16 @@ use fj_core::algorithms::approx::{InvalidTolerance, Tolerance};
 use fj_math::Scalar;
 
 /// Standardized CLI for Fornjot models
+///
+/// This is completely optional, as models are just Rust code and don't need any
+/// kind of CLI interface. It is useful, however, to provide a standardized
+/// interface for viewing and exporting models, and is used for Fornjot's
+/// example models and the testing infrastructure they are part of.
+///
+/// You might not want to use this struct directly. [`handle_model`] Provides a
+/// more high-level and convenient interface.
+///
+/// [`handle_model`]: crate::handle_model()
 #[derive(clap::Parser)]
 pub struct Args {
     /// Export model to this path