context struct first impl

.vscode/c_cpp_properties.json

@@ -0,0 +1,16 @@
+{
+    "configurations": [
+        {
+            "name": "Linux",
+            "includePath": [
+                "${workspaceFolder}/**"
+            ],
+            "defines": [],
+            "compilerPath": "/usr/bin/clang",
+            "cStandard": "c11",
+            "cppStandard": "c++17",
+            "intelliSenseMode": "clang-x64"
+        }
+    ],
+    "version": 4
+}

src/context.rs

@@ -0,0 +1,65 @@
+use std::any::{Any, TypeId};
+use std::collections::HashMap;
+
+#[derive(Default)]
+pub struct Context {
+    container: HashMap<TypeId, Box<dyn Any>>,
+}
+
+impl Context {
+    pub fn get<T: 'static>(&self) -> Option<&T> {
+        self.container
+            .get(&TypeId::of::<T>())
+            .map(|boxed| boxed.downcast_ref().unwrap())
+    }
+
+    pub fn get_mut<T: 'static>(&mut self) -> Option<&mut T> {
+        self.container
+            .get_mut(&TypeId::of::<T>())
+            .map(|boxed| boxed.downcast_mut().unwrap())
+    }
+
+    pub fn set<T: 'static>(&mut self, t: T) {
+        self.container.insert(TypeId::of::<T>(), Box::from(t));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_set_and_get() {
+        // Given Context
+        let mut context = Context::default();
+        // And values
+        context.set(1_u32);
+        context.set(String::from("text"));
+
+        // When
+        let num: &u32 = context.get().unwrap();
+        let text: &String = context.get().unwrap();
+
+        // Then
+        assert_eq!(*num, 1);
+        assert_eq!(text, "text");
+    }
+
+    #[test]
+    fn test_set_and_get_mut() {
+        // Given Context
+        let mut context = Context::default();
+        // And values
+        context.set(1_u32);
+
+        // When
+        {
+            let num: &mut u32 = context.get_mut().unwrap();
+            *num = 2;
+        }
+        let num: &u32 = context.get().unwrap();
+
+        // Then
+        assert_eq!(*num, 2);
+    }
+}

src/lib.rs

@@ -1,7 +1 @@
-#[cfg(test)]
+pub mod context;
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
-}