Create try_from.rs

Author: ztk37

rust/try_from.rs

@@ -0,0 +1,35 @@
+#[derive(Debug, Clone, Copy)]
+pub enum ABC {
+    A,
+    B,
+    C
+}
+
+impl TryFrom<i32> for ABC {
+    type Error = ();
+
+    fn try_from(n: i32) -> Result<Self, Self::Error> {
+        match n {
+            0 => Ok(ABC::A),
+            1 => Ok(ABC::B),
+            2 => Ok(ABC::C),
+            _ => Err(())
+        }
+    }
+}
+
+fn add(a: i64, b: i64) -> i64 {
+    a + b
+}
+
+fn main() {
+    let abc: Result<ABC, ()> = TryFrom::try_from(3);
+
+    match abc {
+        Ok(inner) => println!("{:?}", inner),
+        Err(()) => println!("can't convert to ABC")
+    }
+
+    println!("{}", add(4, 5));
+    println!("{:?}", abc);
+}