From: Martin Pitt <martin@piware.de>
Date: Sun, 29 Aug 2021 14:21:01 +0000 (+0200)
Subject: concepts: Add Post.reject() transition
X-Git-Url: https://piware.de/gitweb/?a=commitdiff_plain;h=6cf2fd87f634bb24ca0ab801a8ba3fbfff1ac418;p=learn-rust.git

concepts: Add Post.reject() transition
---

diff --git a/concepts/src/lib.rs b/concepts/src/lib.rs
index bb15eeb..923b80b 100644
--- a/concepts/src/lib.rs
+++ b/concepts/src/lib.rs
@@ -137,11 +137,16 @@ impl Post {
     pub fn approve(&mut self) {
         self.state = self.state.approve();
     }
+
+    pub fn reject(&mut self) {
+        self.state = self.state.reject();
+    }
 }
 
 trait State {
     fn request_review(&self) -> Box<dyn State>;
     fn approve(&self) -> Box<dyn State>;
+    fn reject(&self) -> Box<dyn State>;
 
     #[allow(unused_variables)]
     fn content<'a>(&self, post: &'a Post) -> &'a str {
@@ -159,6 +164,10 @@ impl State for Draft {
         // don't change state
         Box::new(Self {})
     }
+
+    fn reject(&self) -> Box<dyn State> {
+        Box::new(Self {})
+    }
 }
 
 struct PendingReview {}
@@ -170,6 +179,10 @@ impl State for PendingReview {
     fn approve(&self) -> Box<dyn State> {
         Box::new(Published {})
     }
+
+    fn reject(&self) -> Box<dyn State> {
+        Box::new(Draft {})
+    }
 }
 
 struct Published {}
@@ -182,6 +195,10 @@ impl State for Published {
         Box::new(Published {})
     }
 
+    fn reject(&self) -> Box<dyn State> {
+        Box::new(Self {})
+    }
+
     fn content<'a>(&self, post: &'a Post) -> &'a str {
         &post.content
     }
diff --git a/concepts/src/main.rs b/concepts/src/main.rs
index f9eafe9..3e9bbbd 100644
--- a/concepts/src/main.rs
+++ b/concepts/src/main.rs
@@ -256,6 +256,12 @@ fn test_dyn_traits() {
     post.request_review();
     assert_eq!("", post.content());
 
+    post.reject();
+    assert_eq!("", post.content());
+
+    post.request_review();
+    assert_eq!("", post.content());
+
     post.approve();
     assert_eq!(text, post.content());
 }