From bac5c02bd825b84658ca477f0b30d2fdac72d4a0 Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Wed, 6 Feb 2019 14:28:09 -0500
Subject: [PATCH] Add trait object example

---
 .idea/misc.xml      |   2 +
 .idea/rust.iml      |   9 +++
 .idea/workspace.xml | 170 ++++++++++++++++++++++----------------------
 gui/Cargo.toml      |   7 ++
 gui/src/lib.rs      |  48 +++++++++++++
 gui/src/main.rs     |  36 ++++++++++
 6 files changed, 187 insertions(+), 85 deletions(-)
 create mode 100644 gui/Cargo.toml
 create mode 100644 gui/src/lib.rs
 create mode 100644 gui/src/main.rs

diff --git a/.idea/misc.xml b/.idea/misc.xml
index a6db409..69ba99e 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -32,6 +32,8 @@
     <cargoProject FILE="$PROJECT_DIR$/mutex/Cargo.toml" />
     <cargoProject FILE="$PROJECT_DIR$/oop/Cargo.toml" />
     <cargoProject FILE="$PROJECT_DIR$/twelve_days_of_christmas/Cargo.toml" />
+    <cargoProject FILE="$PROJECT_DIR$/trait_objects/Cargo.toml" />
+    <cargoProject FILE="$PROJECT_DIR$/gui/Cargo.toml" />
   </component>
   <component name="ComposerJsonPluginSettings">
     <unboundedVersionInspectionSettings>
diff --git a/.idea/rust.iml b/.idea/rust.iml
index 657a62e..8f1c362 100644
--- a/.idea/rust.iml
+++ b/.idea/rust.iml
@@ -130,6 +130,13 @@
       <sourceFolder url="file://$MODULE_DIR$/twelve_days_of_christmas/examples" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/twelve_days_of_christmas/tests" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/twelve_days_of_christmas/benches" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/gui/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/trait_objects/examples" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/trait_objects/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/trait_objects/benches" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/gui/examples" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/gui/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/gui/benches" isTestSource="true" />
       <excludeFolder url="file://$MODULE_DIR$/add/add-one/target" />
       <excludeFolder url="file://$MODULE_DIR$/add/adder/target" />
       <excludeFolder url="file://$MODULE_DIR$/adder/target" />
@@ -142,6 +149,7 @@
       <excludeFolder url="file://$MODULE_DIR$/functions/target" />
       <excludeFolder url="file://$MODULE_DIR$/generics/target" />
       <excludeFolder url="file://$MODULE_DIR$/guessing_game/target" />
+      <excludeFolder url="file://$MODULE_DIR$/gui/target" />
       <excludeFolder url="file://$MODULE_DIR$/interior_mutability/target" />
       <excludeFolder url="file://$MODULE_DIR$/lifetimes/target" />
       <excludeFolder url="file://$MODULE_DIR$/loops/target" />
@@ -159,6 +167,7 @@
       <excludeFolder url="file://$MODULE_DIR$/smart_pointers/target" />
       <excludeFolder url="file://$MODULE_DIR$/structs/target" />
       <excludeFolder url="file://$MODULE_DIR$/threads/target" />
+      <excludeFolder url="file://$MODULE_DIR$/trait_objects/target" />
       <excludeFolder url="file://$MODULE_DIR$/twelve_days_of_christmas/target" />
       <excludeFolder url="file://$MODULE_DIR$/variables/target" />
     </content>
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 5b7d892..3883477 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -13,21 +13,7 @@
     <option name="LAST_RESOLUTION" value="IGNORE" />
   </component>
   <component name="FileEditorManager">
-    <leaf>
-      <file pinned="false" current-in-tab="true">
-        <entry file="file://$PROJECT_DIR$/oop/src/lib.rs">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="784">
-              <caret line="49" column="29" selection-start-line="49" selection-start-column="29" selection-end-line="49" selection-end-column="29" />
-              <folding>
-                <element signature="e#510#511#0" expanded="true" />
-                <element signature="e#537#538#0" expanded="true" />
-              </folding>
-            </state>
-          </provider>
-        </entry>
-      </file>
-    </leaf>
+    <leaf />
   </component>
   <component name="FileTemplateManagerImpl">
     <option name="RECENT_TEMPLATES">
@@ -41,11 +27,13 @@
       <find>ftoc</find>
       <find>expensive_closure(intensity)</find>
       <find>ordinals</find>
+      <find>///</find>
     </findStrings>
     <replaceStrings>
       <replace>f_to_c</replace>
       <replace>expensive_result.value(intensity)</replace>
       <replace>ORDINALS</replace>
+      <replace>//!</replace>
     </replaceStrings>
   </component>
   <component name="Git.Settings">
@@ -54,11 +42,6 @@
   <component name="IdeDocumentHistory">
     <option name="CHANGED_PATHS">
       <list>
-        <option value="$PROJECT_DIR$/functions/src/main.rs" />
-        <option value="$PROJECT_DIR$/branches/src/main.rs" />
-        <option value="$PROJECT_DIR$/ctof/src/main.rs" />
-        <option value="$PROJECT_DIR$/ftoc/src/main.rs" />
-        <option value="$PROJECT_DIR$/loops/src/main.rs" />
         <option value="$PROJECT_DIR$/scope/src/main.rs" />
         <option value="$PROJECT_DIR$/references/src/main.rs" />
         <option value="$PROJECT_DIR$/slices/src/main.rs" />
@@ -105,6 +88,11 @@
         <option value="$PROJECT_DIR$/twelve_days_of_christmas/Cargo.toml" />
         <option value="$PROJECT_DIR$/twelve_days_of_christmas/src/main.rs" />
         <option value="$PROJECT_DIR$/oop/src/lib.rs" />
+        <option value="$PROJECT_DIR$/trait_objects/src/lib.rs" />
+        <option value="$PROJECT_DIR$/trait_objects/src/main.rs" />
+        <option value="$PROJECT_DIR$/trait_objects/Cargo.toml" />
+        <option value="$PROJECT_DIR$/gui/src/main.rs" />
+        <option value="$PROJECT_DIR$/gui/src/lib.rs" />
       </list>
     </option>
   </component>
@@ -135,6 +123,17 @@
               <item name="rust" type="3d21c010:ScopeViewTreeModel$ProjectNode" />
               <item name="rust" type="2674bda8:ScopeViewTreeModel$GroupNode" />
             </path>
+            <path>
+              <item name="rust" type="3d21c010:ScopeViewTreeModel$ProjectNode" />
+              <item name="rust" type="2674bda8:ScopeViewTreeModel$GroupNode" />
+              <item name="twelve_days_of_christmas" type="9f88c78c:ScopeViewTreeModel$FileNode" />
+            </path>
+            <path>
+              <item name="rust" type="3d21c010:ScopeViewTreeModel$ProjectNode" />
+              <item name="rust" type="2674bda8:ScopeViewTreeModel$GroupNode" />
+              <item name="twelve_days_of_christmas" type="9f88c78c:ScopeViewTreeModel$FileNode" />
+              <item name="src" type="9f88c78c:ScopeViewTreeModel$FileNode" />
+            </path>
           </expand>
           <select />
         </subPane>
@@ -166,7 +165,7 @@
   </component>
   <component name="PropertiesComponent">
     <property name="JavaScriptWeakerCompletionTypeGuess" value="true" />
-    <property name="com.android.tools.idea.instantapp.provision.ProvisionBeforeRunTaskProvider.myTimeStamp" value="1549478828057" />
+    <property name="com.android.tools.idea.instantapp.provision.ProvisionBeforeRunTaskProvider.myTimeStamp" value="1549480480153" />
     <property name="javascript.nodejs.core.library.configured.version" value="7.1.0" />
     <property name="js.eslint.eslintPackage" value="$USER_HOME$/.yarn-config/global/node_modules/.bin/eslint" />
     <property name="js.eslint.nodeInterpreter" value="project" />
@@ -194,7 +193,7 @@
       </list>
     </option>
   </component>
-  <component name="RunManager" selected="Cargo Command.Run twelve_days_of_christmas">
+  <component name="RunManager" selected="Cargo Command.Run gui">
     <configuration name="&lt;template&gt;" type="TestNG" default="true" selected="false">
       <option name="MAIN_CLASS_NAME" />
       <option name="VM_PARAMETERS" value="-ea" />
@@ -213,6 +212,16 @@
         <option name="Make" enabled="true" />
       </method>
     </configuration>
+    <configuration name="Run gui" type="CargoCommandRunConfiguration" factoryName="Cargo Command" temporary="true">
+      <option name="channel" value="DEFAULT" />
+      <option name="command" value="run --package gui --bin gui" />
+      <option name="allFeatures" value="false" />
+      <option name="nocapture" value="false" />
+      <option name="backtrace" value="SHORT" />
+      <option name="workingDirectory" value="file://$PROJECT_DIR$/gui" />
+      <envs />
+      <method v="2" />
+    </configuration>
     <configuration name="Run mutex" type="CargoCommandRunConfiguration" factoryName="Cargo Command" temporary="true">
       <option name="channel" value="DEFAULT" />
       <option name="command" value="run --package mutex --bin mutex" />
@@ -223,26 +232,6 @@
       <envs />
       <method v="2" />
     </configuration>
-    <configuration name="Run reference_counting" type="CargoCommandRunConfiguration" factoryName="Cargo Command" temporary="true">
-      <option name="channel" value="DEFAULT" />
-      <option name="command" value="run --package reference_counting --bin reference_counting" />
-      <option name="allFeatures" value="false" />
-      <option name="nocapture" value="false" />
-      <option name="backtrace" value="SHORT" />
-      <option name="workingDirectory" value="file://$PROJECT_DIR$/reference_counting" />
-      <envs />
-      <method v="2" />
-    </configuration>
-    <configuration name="Run reference_cycles" type="CargoCommandRunConfiguration" factoryName="Cargo Command" temporary="true">
-      <option name="channel" value="DEFAULT" />
-      <option name="command" value="run --package reference_cycles --bin reference_cycles" />
-      <option name="allFeatures" value="false" />
-      <option name="nocapture" value="false" />
-      <option name="backtrace" value="SHORT" />
-      <option name="workingDirectory" value="file://$PROJECT_DIR$/reference_cycles" />
-      <envs />
-      <method v="2" />
-    </configuration>
     <configuration name="Run threads" type="CargoCommandRunConfiguration" factoryName="Cargo Command" temporary="true">
       <option name="channel" value="DEFAULT" />
       <option name="command" value="run --package threads --bin threads" />
@@ -263,6 +252,16 @@
       <envs />
       <method v="2" />
     </configuration>
+    <configuration name="Test lib::tests" type="CargoCommandRunConfiguration" factoryName="Cargo Command" temporary="true">
+      <option name="channel" value="DEFAULT" />
+      <option name="command" value="test --package oop --lib tests" />
+      <option name="allFeatures" value="false" />
+      <option name="nocapture" value="false" />
+      <option name="backtrace" value="SHORT" />
+      <option name="workingDirectory" value="file://$PROJECT_DIR$/oop" />
+      <envs />
+      <method v="2" />
+    </configuration>
     <configuration default="true" type="JUnit" factoryName="JUnit">
       <option name="TEST_OBJECT" value="class" />
       <option name="WORKING_DIRECTORY" value="$MODULE_DIR$" />
@@ -272,18 +271,15 @@
     </configuration>
     <recent_temporary>
       <list>
+        <item itemvalue="Cargo Command.Run gui" />
+        <item itemvalue="Cargo Command.Test lib::tests" />
         <item itemvalue="Cargo Command.Run twelve_days_of_christmas" />
         <item itemvalue="Cargo Command.Run mutex" />
         <item itemvalue="Cargo Command.Run threads" />
-        <item itemvalue="Cargo Command.Run reference_cycles" />
-        <item itemvalue="Cargo Command.Run reference_counting" />
       </list>
     </recent_temporary>
   </component>
   <component name="TestHistory">
-    <history-entry file="Test_tests__it_works - 2019.01.31 at 14h 06m 37s.xml">
-      <configuration name="Test tests::it_works" configurationId="CargoCommandRunConfiguration" />
-    </history-entry>
     <history-entry file="Test_tests__greeting_contains_name - 2019.01.31 at 14h 18m 57s.xml">
       <configuration name="Test tests::greeting_contains_name" configurationId="CargoCommandRunConfiguration" />
     </history-entry>
@@ -311,13 +307,15 @@
     <history-entry file="Test_lib__tests - 2019.02.05 at 10h 33m 57s.xml">
       <configuration name="Test lib::tests" configurationId="CargoCommandRunConfiguration" />
     </history-entry>
+    <history-entry file="Test_lib__tests - 2019.02.06 at 13h 49m 17s.xml">
+      <configuration name="Test lib::tests" configurationId="CargoCommandRunConfiguration" />
+    </history-entry>
   </component>
   <component name="ToolWindowManager">
     <frame x="1680" y="-410" width="1050" height="1657" extended-state="6" />
-    <editor active="true" />
     <layout>
-      <window_info active="true" content_ui="combo" id="Project" order="0" sideWeight="0.49644932" visible="true" weight="0.26141885" />
-      <window_info id="Structure" order="1" sideWeight="0.50355065" side_tool="true" visible="true" weight="0.26141885" />
+      <window_info active="true" content_ui="combo" id="Project" order="0" sideWeight="0.4960707" visible="true" weight="0.26141885" />
+      <window_info id="Structure" order="1" sideWeight="0.50392926" side_tool="true" visible="true" weight="0.26141885" />
       <window_info id="Image Layers" order="2" />
       <window_info id="Designer" order="3" />
       <window_info id="Capture Tool" order="4" />
@@ -333,7 +331,7 @@
       <window_info anchor="bottom" id="Docker" order="7" show_stripe_button="false" />
       <window_info anchor="bottom" id="Version Control" order="8" />
       <window_info anchor="bottom" id="Inspection Results" order="9" weight="0.32979318" />
-      <window_info anchor="bottom" id="Terminal" order="10" weight="0.3428018" />
+      <window_info anchor="bottom" id="Terminal" order="10" visible="true" weight="0.3428018" />
       <window_info anchor="bottom" id="Event Log" order="11" side_tool="true" />
       <window_info anchor="right" id="Commander" order="0" weight="0.4" />
       <window_info anchor="right" id="Ant Build" order="1" weight="0.25" />
@@ -347,31 +345,6 @@
     <option name="version" value="1" />
   </component>
   <component name="editorHistoryManager">
-    <entry file="file://$PROJECT_DIR$/branches/src/main.rs">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="160">
-          <caret line="10" selection-start-line="10" selection-end-line="10" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/guessing_game/src/main.rs">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="192">
-          <caret line="12" selection-start-line="12" selection-end-line="12" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/ctof/src/main.rs">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="304">
-          <caret line="19" column="8" selection-start-line="19" selection-start-column="8" selection-end-line="19" selection-end-column="8" />
-          <folding>
-            <element signature="e#450#451#0" expanded="true" />
-            <element signature="e#475#476#0" expanded="true" />
-          </folding>
-        </state>
-      </provider>
-    </entry>
     <entry file="file://$PROJECT_DIR$/ftoc/src/main.rs">
       <provider selected="true" editor-type-id="text-editor">
         <state relative-caret-position="352">
@@ -760,13 +733,6 @@
         </state>
       </provider>
     </entry>
-    <entry file="file://$PROJECT_DIR$/twelve_days_of_christmas/src/main.rs">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="112">
-          <caret line="7" column="27" lean-forward="true" selection-start-line="7" selection-start-column="27" selection-end-line="7" selection-end-column="27" />
-        </state>
-      </provider>
-    </entry>
     <entry file="file://$PROJECT_DIR$/twelve_days_of_christmas/Cargo.toml">
       <provider selected="true" editor-type-id="text-editor">
         <state relative-caret-position="32">
@@ -776,11 +742,45 @@
     </entry>
     <entry file="file://$PROJECT_DIR$/oop/src/lib.rs">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="784">
-          <caret line="49" column="29" selection-start-line="49" selection-start-column="29" selection-end-line="49" selection-end-column="29" />
+        <state relative-caret-position="720">
+          <caret line="45" lean-forward="true" selection-start-line="45" selection-end-line="45" />
           <folding>
             <element signature="e#510#511#0" expanded="true" />
             <element signature="e#537#538#0" expanded="true" />
+            <element signature="e#956#957#0" expanded="true" />
+            <element signature="e#992#993#0" expanded="true" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/gui/Cargo.toml">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="112">
+          <caret line="7" lean-forward="true" selection-start-line="7" selection-end-line="7" />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/twelve_days_of_christmas/src/main.rs">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="144">
+          <caret line="9" column="25" selection-start-line="9" selection-start-column="25" selection-end-line="9" selection-end-column="25" />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/gui/src/main.rs">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="576">
+          <caret line="36" lean-forward="true" selection-start-line="36" selection-end-line="36" />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/gui/src/lib.rs">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="768">
+          <caret line="48" lean-forward="true" selection-start-line="48" selection-end-line="48" />
+          <folding>
+            <element signature="e#371#372#0" expanded="true" />
+            <element signature="e#407#408#0" expanded="true" />
           </folding>
         </state>
       </provider>
diff --git a/gui/Cargo.toml b/gui/Cargo.toml
new file mode 100644
index 0000000..0f694ce
--- /dev/null
+++ b/gui/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "gui"
+version = "0.1.0"
+authors = ["Timothy Warren <twarren@nabancard.com>"]
+edition = "2018"
+
+[dependencies]
diff --git a/gui/src/lib.rs b/gui/src/lib.rs
new file mode 100644
index 0000000..31a4d7f
--- /dev/null
+++ b/gui/src/lib.rs
@@ -0,0 +1,48 @@
+//! An implementation of a "trait object",
+//! which allows dynamic dispatch for implementing types,
+//! even allowing disparate types to be called, unlike a
+//! generic, which requires one specific implementation.
+//!
+//! Trait objects have some limitations (They must be "object-safe"):
+//!     * Methods can not return `Self`
+//!     * Methods can not have generic type parameters
+
+/// The base trait definition
+pub trait Draw {
+    fn draw(&self);
+}
+
+/// A struct able to utilize the "trait object", via the Box<dyn Draw> type
+pub struct Screen {
+    pub components: Vec<Box<dyn Draw>>,
+}
+
+/// A method able to call the draw method on any objects
+/// implementing the Draw "trait object"
+impl Screen {
+    pub fn run(&self) {
+        for component in self.components.iter() {
+            component.draw();
+        }
+    }
+}
+
+pub struct Button {
+    pub width: u32,
+    pub height: u32,
+    pub label: String,
+}
+
+impl Draw for Button {
+    fn draw(&self) {
+        // code to actually draw a button
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}
diff --git a/gui/src/main.rs b/gui/src/main.rs
new file mode 100644
index 0000000..fcaf707
--- /dev/null
+++ b/gui/src/main.rs
@@ -0,0 +1,36 @@
+use gui::{Button, Draw, Screen};
+
+struct SelectBox {
+    width: u32,
+    height: u32,
+    options: Vec<String>,
+}
+
+impl Draw for SelectBox {
+    fn draw(&self) {
+        // code to actually draw a select box
+    }
+}
+
+fn main() {
+    let screen = Screen {
+        components: vec![
+            Box::new(SelectBox {
+                width: 75,
+                height: 10,
+                options: vec![
+                    String::from("Yes"),
+                    String::from("Maybe"),
+                    String::from("No")
+                ],
+            }),
+            Box::new(Button {
+                width: 50,
+                height: 10,
+                label: String::from("OK"),
+            }),
+        ],
+    };
+
+    screen.run();
+}