Optional and Result for optional parameters and functions that may fail.

src/main.rs

@@ -1,21 +1,15 @@
-enum Color {
-    RGB(f32, f32, f32),
-    RGBA(f32, f32, f32, f32),
-    CMYK(f32, f32, f32, f32),
-    YUV(f32, f32, f32),
-}
-
-fn color_to_string(color: Color) -> String {
-    match color {
-        Color::RGB(red, green, blue) => String::from("RGB"),
-        Color::RGBA(red, green, blue, alpha) => String::from("RGBA"),
-        Color::CMYK(cyan, magenta, yellow, key) => String::from("CMYK"),
-        Color::YUV(y, u, v) => String::from("YUV"),
+fn add_10(value: Option<u32>) -> Result<u32, String> {
+    match value {
+        Some(v) => Ok(v + 10),
+        None => Err(String::from("value was empty")),
     }
 }
 
 fn main() {
-    let color = Color::RGB(1.0, 0.0, 0.0);
+    let value = add_10(Some(23));
 
-    println!("Color: {}", color_to_string(color));
+    match value {
+        Ok(v) => println!("Result was: {}", v),
+        Err(e) => println!("Operatation failed. Reason was: {}", e),
+    }
 }