cool stuff functors

Chapter07/functor_pattern.rs

@@ -1,5 +1,59 @@
 use std::collections::{HashSet};
 
+struct WebCamera;
+#[derive(Debug)]
+enum VisibleEmotion {
+   Anger,
+   Contempt,
+   Disgust,
+   Fear,
+   Happiness,
+   Neutral,
+   Sadness,
+   Surprise
+}
+#[derive(Debug,Clone)]
+struct BoundingBox {
+   top: u64,
+   left: u64,
+   height: u64,
+   width: u64
+}
+#[derive(Debug)]
+enum CameraFilters {
+   Sparkles,
+   Rain,
+   Fire,
+   Disco
+}
+
+impl WebCamera {
+   fn map_emotion<T,F>(&self, translate: F) -> Vec<(BoundingBox,T)>
+      where F: Fn(VisibleEmotion) -> T {
+      //Simulate emotion extracted from WebCamera
+      vec![
+         (BoundingBox { top: 1, left: 1, height: 1, width: 1 }, VisibleEmotion::Anger),
+         (BoundingBox { top: 1, left: 1, height: 1, width: 1 }, VisibleEmotion::Sadness),
+         (BoundingBox { top: 4, left: 4, height: 1, width: 1 }, VisibleEmotion::Surprise),
+         (BoundingBox { top: 8, left: 1, height: 1, width: 1 }, VisibleEmotion::Neutral)
+      ].into_iter().map(|(bb,emt)| {
+        (bb, translate(emt))
+      }).collect::<Vec<(BoundingBox,T)>>()
+   }
+   fn flatmap_emotion<T,F,U:IntoIterator<Item=T>>(&self, mut translate: F) -> Vec<(BoundingBox,T)>
+      where F: FnMut(VisibleEmotion) -> U {
+      //Simulate emotion extracted from WebCamera
+      vec![
+         (BoundingBox { top: 1, left: 1, height: 1, width: 1 }, VisibleEmotion::Anger),
+         (BoundingBox { top: 1, left: 1, height: 1, width: 1 }, VisibleEmotion::Sadness),
+         (BoundingBox { top: 4, left: 4, height: 1, width: 1 }, VisibleEmotion::Surprise),
+         (BoundingBox { top: 8, left: 1, height: 1, width: 1 }, VisibleEmotion::Neutral)
+      ].into_iter().flat_map(|(bb,emt)| {
+        translate(emt).into_iter().map(move |t| (bb.clone(), t))
+      }).collect::<Vec<(BoundingBox,T)>>()
+   }
+}
+
 fn main()
 {
    let m: Vec<u64> = vec![1, 2, 3];
@@ -25,4 +79,32 @@ fn main()
    let s: HashSet<u64> = v.iter().cloned().map(|x| x/2).collect();
    println!("{:?}", v);
    println!("{:?}", s);
+
+   let camera = WebCamera;
+   let emotes: Vec<(BoundingBox,VisibleEmotion)> = camera.map_emotion(|emt| {
+      match emt {
+        VisibleEmotion::Anger |
+        VisibleEmotion::Contempt |
+        VisibleEmotion::Disgust |
+        VisibleEmotion::Fear |
+        VisibleEmotion::Sadness => VisibleEmotion::Happiness,
+        VisibleEmotion::Neutral |
+        VisibleEmotion::Happiness |
+        VisibleEmotion::Surprise => VisibleEmotion::Sadness
+      }
+   });
+   let filters: Vec<(BoundingBox,CameraFilters)> = camera.flatmap_emotion(|emt| {
+      match emt {
+        VisibleEmotion::Anger |
+        VisibleEmotion::Contempt |
+        VisibleEmotion::Disgust |
+        VisibleEmotion::Fear |
+        VisibleEmotion::Sadness => vec![CameraFilters::Sparkles, CameraFilters::Rain],
+        VisibleEmotion::Neutral |
+        VisibleEmotion::Happiness |
+        VisibleEmotion::Surprise => vec![CameraFilters::Disco]
+      }
+   });
+   println!("{:?}",emotes);
+   println!("{:?}",filters);
 }