Error types everywhere instead of String

examples/animation.rs

@@ -1,4 +1,5 @@
 extern crate sdl2;
+
 use std::path::Path;
 
 use sdl2::event::Event;
@@ -7,15 +8,15 @@ use sdl2::rect::Rect;
 use sdl2::rect::Point;
 use std::time::Duration;
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
     let window = video_subsystem.window("SDL2", 640, 480)
-        .position_centered().build().map_err(|e| e.to_string())?;
+        .position_centered().build()?;
 
     let mut canvas = window.into_canvas()
-        .accelerated().build().map_err(|e| e.to_string())?;
+        .accelerated().build()?;
     let texture_creator = canvas.texture_creator();
 
     canvas.set_draw_color(sdl2::pixels::Color::RGBA(0,0,0,255));
@@ -27,8 +28,7 @@ fn main() -> Result<(), String> {
     // animation sheet and extras are available from
     // https://opengameart.org/content/a-platformer-in-the-forest
     let temp_surface = sdl2::surface::Surface::load_bmp(Path::new("assets/characters.bmp"))?;
-    let texture = texture_creator.create_texture_from_surface(&temp_surface)
-        .map_err(|e| e.to_string())?;
+    let texture = texture_creator.create_texture_from_surface(&temp_surface)?;
 
     let frames_per_anim = 4;
     let sprite_tile_size = (32,32);

examples/audio-capture-and-replay.rs

@@ -39,7 +39,7 @@ impl AudioCallback for Recording {
     }
 }
 
-fn record(audio_subsystem: &AudioSubsystem, desired_spec: &AudioSpecDesired) -> Result<Vec<i16>, String> {
+fn record(audio_subsystem: &AudioSubsystem, desired_spec: &AudioSpecDesired) -> Result<Vec<i16>, Box<dyn std::error::Error>> {
     println!("Capturing {:} seconds... Please rock!", RECORDING_LENGTH_SECONDS);
 
     let (done_sender, done_receiver) = mpsc::channel();
@@ -100,7 +100,7 @@ impl AudioCallback for SoundPlayback {
     }
 }
 
-fn replay_recorded_vec(audio_subsystem: &AudioSubsystem, desired_spec: &AudioSpecDesired, recorded_vec: Vec<i16>) -> Result<(), String> {
+fn replay_recorded_vec(audio_subsystem: &AudioSubsystem, desired_spec: &AudioSpecDesired, recorded_vec: Vec<i16>) -> Result<(), Box<dyn std::error::Error>> {
     println!("Playing...");
 
     let playback_device = audio_subsystem.open_playback(None, desired_spec, |spec| {
@@ -121,7 +121,7 @@ fn replay_recorded_vec(audio_subsystem: &AudioSubsystem, desired_spec: &AudioSpe
 }
 
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let audio_subsystem = sdl_context.audio()?;
 

examples/audio-queue-squarewave.rs

@@ -24,7 +24,7 @@ fn gen_wave(bytes_to_write: i32) -> Vec<i16> {
     result
 }
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let audio_subsystem = sdl_context.audio()?;
 

examples/audio-squarewave.rs

@@ -21,7 +21,7 @@ impl AudioCallback for SquareWave {
     }
 }
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let audio_subsystem = sdl_context.audio()?;
 

examples/audio-wav.rs

@@ -38,7 +38,7 @@ impl AudioCallback for Sound {
     }
 }
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let wav_file : Cow<'static, Path> = match std::env::args().nth(1) {
         None => Cow::from(Path::new("./assets/sine.wav")),
         Some(s) => Cow::from(PathBuf::from(s))

examples/audio-whitenoise.rs

@@ -21,7 +21,7 @@ impl AudioCallback for MyCallback {
     }
 }
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let audio_subsystem = sdl_context.audio()?;
 

examples/cursor.rs

@@ -10,16 +10,15 @@ use sdl2::pixels::Color;
 use sdl2::rect::Rect;
 use sdl2::surface::Surface;
 
-pub fn run(png: &Path) -> Result<(), String> {
+pub fn run(png: &Path) -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
     let _image_context = sdl2::image::init(InitFlag::PNG | InitFlag::JPG)?;
     let window = video_subsystem.window("rust-sdl2 demo: Cursor", 800, 600)
       .position_centered()
-      .build()
-      .map_err(|e| e.to_string())?;
+      .build()?;
 
-    let mut canvas = window.into_canvas().software().build().map_err(|e| e.to_string())?;
+    let mut canvas = window.into_canvas().software().build()?;
 
     let surface = Surface::from_file(png)
         .map_err(|err| format!("failed to load cursor image: {}", err))?;
@@ -53,7 +52,7 @@ pub fn run(png: &Path) -> Result<(), String> {
 }
 
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let args: Vec<_> = env::args().collect();
 
     if args.len() < 2 {

examples/demo.rs

@@ -5,17 +5,16 @@ use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
 use std::time::Duration;
 
-pub fn main() -> Result<(), String> {
+pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
     let window = video_subsystem.window("rust-sdl2 demo: Video", 800, 600)
         .position_centered()
         .opengl()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
-    let mut canvas = window.into_canvas().build().map_err(|e| e.to_string())?;
+    let mut canvas = window.into_canvas().build()?;
 
     canvas.set_draw_color(Color::RGB(255, 0, 0));
     canvas.clear();

examples/events.rs

@@ -5,17 +5,16 @@ use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
 use std::time::Duration;
 
-pub fn main() -> Result<(), String> {
+pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
     let window = video_subsystem.window("rust-sdl2 demo: Events", 800, 600)
         .position_centered()
         .resizable()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
-    let mut canvas = window.into_canvas().build().map_err(|e| e.to_string())?;
+    let mut canvas = window.into_canvas().build()?;
 
     canvas.set_draw_color(Color::RGB(255, 0, 0));
     canvas.clear();

examples/game-controller.rs

@@ -1,6 +1,6 @@
 extern crate sdl2;
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let game_controller_subsystem = sdl_context.game_controller()?;
 

examples/game-of-life-unsafe-textures.rs

@@ -126,13 +126,13 @@ mod game_of_life {
 }
 
 #[cfg(feature = "unsafe_textures")]
-fn dummy_texture<'a>(canvas: &mut Canvas<Window>) -> Result<(Texture, Texture), String> {
+fn dummy_texture<'a>(canvas: &mut Canvas<Window>) -> Result<(Texture, Texture), Box<dyn std::error::Error>> {
     enum TextureColor {
         Yellow,
         White,
     };
-    let mut square_texture1 = canvas.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE).map_err(|e| e.to_string())?;
-    let mut square_texture2 = canvas.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE).map_err(|e| e.to_string())?;
+    let mut square_texture1 = canvas.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE)?;
+    let mut square_texture2 = canvas.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE)?;
         // let's change the textures we just created
     {
         let textures = vec![
@@ -198,13 +198,13 @@ fn dummy_texture<'a>(canvas: &mut Canvas<Window>) -> Result<(Texture, Texture),
                     }
                 }
             }
-        }).map_err(|e| e.to_string())?;
+        })?;
     }
     Ok((square_texture1, square_texture2))
 }
 
 #[cfg(feature = "unsafe_textures")]
-pub fn main() -> Result<(), String> {
+pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
@@ -217,15 +217,14 @@ pub fn main() -> Result<(), String> {
                 SQUARE_SIZE*PLAYGROUND_WIDTH,
                 SQUARE_SIZE*PLAYGROUND_HEIGHT)
         .position_centered()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
     // the canvas allows us to both manipulate the property of the window and to change its content
     // via hardware or software rendering. See CanvasBuilder for more info.
     let mut canvas = window.into_canvas()
         .target_texture()
         .present_vsync()
-        .build().map_err(|e| e.to_string())?;
+        .build()?;
 
     println!("Using SDL_Renderer \"{}\"", canvas.info().name);
     canvas.set_draw_color(Color::RGB(0, 0, 0));

examples/game-of-life.rs

@@ -115,13 +115,13 @@ mod game_of_life {
     }
 }
 
-fn dummy_texture<'a>(canvas: &mut Canvas<Window>, texture_creator: &'a TextureCreator<WindowContext>) -> Result<(Texture<'a>, Texture<'a>), String> {
+fn dummy_texture<'a>(canvas: &mut Canvas<Window>, texture_creator: &'a TextureCreator<WindowContext>) -> Result<(Texture<'a>, Texture<'a>), Box<dyn std::error::Error>> {
     enum TextureColor {
         Yellow,
         White,
     };
-    let mut square_texture1 = texture_creator.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE).map_err(|e| e.to_string())?;
-    let mut square_texture2 = texture_creator.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE).map_err(|e| e.to_string())?;
+    let mut square_texture1 = texture_creator.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE)?;
+    let mut square_texture2 = texture_creator.create_texture_target(None, SQUARE_SIZE, SQUARE_SIZE)?;
         // let's change the textures we just created
     {
         let textures = vec![
@@ -187,12 +187,12 @@ fn dummy_texture<'a>(canvas: &mut Canvas<Window>, texture_creator: &'a TextureCr
                     }
                 }
             }
-        }).map_err(|e| e.to_string())?;
+        })?;
     }
     Ok((square_texture1, square_texture2))
 }
 
-pub fn main() -> Result<(), String> {
+pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
@@ -205,16 +205,14 @@ pub fn main() -> Result<(), String> {
                 SQUARE_SIZE*PLAYGROUND_WIDTH,
                 SQUARE_SIZE*PLAYGROUND_HEIGHT)
         .position_centered()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
     // the canvas allows us to both manipulate the property of the window and to change its content
     // via hardware or software rendering. See CanvasBuilder for more info.
     let mut canvas = window.into_canvas()
         .target_texture()
         .present_vsync()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
     println!("Using SDL_Renderer \"{}\"", canvas.info().name);
     canvas.set_draw_color(Color::RGB(0, 0, 0));

examples/gfx-demo.rs

@@ -9,16 +9,15 @@ use sdl2::gfx::primitives::DrawRenderer;
 const SCREEN_WIDTH: u32 = 800;
 const SCREEN_HEIGHT: u32 = 600;
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsys = sdl_context.video()?;
     let window = video_subsys.window("rust-sdl2_gfx: draw line & FPSManager", SCREEN_WIDTH, SCREEN_HEIGHT)
         .position_centered()
         .opengl()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
-    let mut canvas = window.into_canvas().build().map_err(|e| e.to_string())?;
+    let mut canvas = window.into_canvas().build()?;
 
     canvas.set_draw_color(pixels::Color::RGB(0, 0, 0));
     canvas.clear();

examples/haptic.rs

@@ -1,6 +1,6 @@
 extern crate sdl2;
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let joystick_subsystem = sdl_context.joystick()?;
     let haptic_subsystem = sdl_context.haptic()?;
@@ -22,8 +22,7 @@ fn main() -> Result<(), String> {
         },
     }).expect("Couldn't open any joystick");
 
-    let mut haptic = haptic_subsystem.open_from_joystick_id(joystick_index)
-        .map_err(|e| e.to_string())?;
+    let mut haptic = haptic_subsystem.open_from_joystick_id(joystick_index)?;
 
     for event in sdl_context.event_pump()?.wait_iter() {
         use sdl2::event::Event;

examples/image-demo.rs

@@ -6,16 +6,15 @@ use sdl2::image::{LoadTexture, InitFlag};
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
 
-pub fn run(png: &Path) -> Result<(), String> {
+pub fn run(png: &Path) -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
     let _image_context = sdl2::image::init(InitFlag::PNG | InitFlag::JPG)?;
     let window = video_subsystem.window("rust-sdl2 demo: Video", 800, 600)
       .position_centered()
-      .build()
-      .map_err(|e| e.to_string())?;
+      .build()?;
 
-    let mut canvas = window.into_canvas().software().build().map_err(|e| e.to_string())?;
+    let mut canvas = window.into_canvas().software().build()?;
     let texture_creator = canvas.texture_creator();
     let texture = texture_creator.load_texture(png)?;
 
@@ -36,7 +35,7 @@ pub fn run(png: &Path) -> Result<(), String> {
     Ok(())
 }
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let args: Vec<_> = env::args().collect();
 
     if args.len() < 2 {

examples/joystick.rs

@@ -1,6 +1,6 @@
 extern crate sdl2;
 
-fn main() -> Result<(), String> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let joystick_subsystem = sdl_context.joystick()?;
 
@@ -22,8 +22,7 @@ fn main() -> Result<(), String> {
     }).expect("Couldn't open any joystick");
 
     // Print the joystick's power level
-    println!("\"{}\" power level: {:?}", joystick.name(), joystick.power_level()
-        .map_err(|e| e.to_string())?);
+    println!("\"{}\" power level: {:?}", joystick.name(), joystick.power_level()?);
 
     let (mut lo_freq, mut hi_freq) = (0, 0);
 

examples/keyboard-state.rs

@@ -5,14 +5,13 @@ use sdl2::keyboard::Keycode;
 use std::collections::HashSet;
 use std::time::Duration;
 
-pub fn main() -> Result<(), String> {
+pub fn main() -> Result<(), Box<dyn std::error::Error>> {
     let sdl_context = sdl2::init()?;
     let video_subsystem = sdl_context.video()?;
 
     let _window = video_subsystem.window("Keyboard", 800, 600)
         .position_centered()
-        .build()
-        .map_err(|e| e.to_string())?;
+        .build()?;
 
     let mut events = sdl_context.event_pump()?;