record progress: try from

exercises/23_conversions/try_from_into.rs

@@ -6,6 +6,7 @@
 
 #![allow(clippy::useless_vec)]
 use std::convert::{TryFrom, TryInto};
+use crate::IntoColorError::BadLen;
 
 #[derive(Debug, PartialEq)]
 struct Color {
@@ -23,27 +24,60 @@ enum IntoColorError {
     IntConversion,
 }
 
-// TODO: Tuple implementation.
+// Tuple implementation.
 // Correct RGB color values must be integers in the 0..=255 range.
 impl TryFrom<(i16, i16, i16)> for Color {
     type Error = IntoColorError;
 
-    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {}
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+        let (red, green, blue) = tuple;
+        Self::from_rgb(red, green, blue)
+    }
+}
+
+impl Color {
+    fn from_rgb(red: i16, green: i16, blue: i16) -> Result<Self, IntoColorError> {
+        if red < 0 || red > 255 {
+            return Err(IntoColorError::IntConversion);
+        }
+        if blue < 0 || blue > 255 {
+            return Err(IntoColorError::IntConversion);
+        }
+        if green < 0 || green > 255 {
+            return Err(IntoColorError::IntConversion);
+        }
+
+        Ok(Color {
+            red: red as u8,
+            green: green as u8,
+            blue: blue as u8
+        })
+    }
 }
 
 // TODO: Array implementation.
 impl TryFrom<[i16; 3]> for Color {
     type Error = IntoColorError;
 
-    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {}
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+        let [red, green, blue] = arr;
+        Self::from_rgb(red, green, blue)
+    }
 }
 
-// TODO: Slice implementation.
 // This implementation needs to check the slice length.
 impl TryFrom<&[i16]> for Color {
     type Error = IntoColorError;
 
-    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {}
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+        if slice.len() != 3 {
+            return Err(BadLen)
+        }
+        let [red, green, blue] = *slice else {
+            return Err(BadLen)
+        };
+        Self::from_rgb(red, green, blue)
+    }
 }
 
 fn main() {