Added examples to the code style

1 files changed, 303 insertions, 41 deletions

diff --git a/contributing.md b/contributing.md
index 775119a..720985e 100644
--- a/contributing.md
+++ b/contributing.md
@@ -18,66 +18,328 @@
 # Code style
 
 - ASCII only
+
+  ```cpp
+  // Good
+  std::string message = "Hello, world!";
+  
+  // Bad
+  std::string message = "こんにちは世界";
+  ```
+
 - Class names are always singular
+
+  ```cpp
+  // Good
+  class Car {};
+  
+  // Bad
+  class Cars {};
+  ```
+
 - Explanatory comments are placed above the line(s) they are explaining
-- Source files should only contain comments that plainly state what the code is
-  supposed to do
-- Explanatory comments in headers may be used to clarify implementation design
-  decisions
-- Formatting nitty-gritty is handled by clang-format/clang-tidy (run `make
-  format` in the root folder of this repository to format all sources files)
-- Header includes are split into paragraphs separated by a blank line. The
-  order is:
+
+  ```cpp
+  // Good
+  // This function adds two numbers
+  int add(int a, int b) {
+      return a + b;
+  }
+  
+  // Bad
+  int add(int a, int b) {
+      return a + b; // This function adds two numbers
+  }
+  ```
+
+- Source files should only contain comments that plainly state what the code is supposed to do
+
+  ```cpp
+  // Good
+  // Initialize the engine
+  engine.init();
+  
+  // Bad
+  // Initialize the engine with default settings and prepare it for running
+  engine.init();
+  ```
+
+- Explanatory comments in headers may be used to clarify implementation design decisions
+
+  ```cpp
+  // Good
+  // This class handles the rendering process
+  class Renderer {};
+  
+  // Bad
+  class Renderer {}; // This class handles the rendering process
+  ```
+
+- Formatting nitty-gritty is handled by clang-format/clang-tidy (run `make format` in the root folder of this repository to format all sources files)
+
+
+- Header includes are split into paragraphs separated by a blank line. The order is:
   1. system headers (using `<`brackets`>`)
   2. relative headers NOT in the same folder as the current file
   3. relative headers in the same folder as the current file
-- When using libraries of which the header include order is important, make
-  sure to separate the include statements using a blank line (clang-format may
-  sort include statements, but does not sort across empty lines).
-- All engine-related code is implemented under the `crepe` namespace,
-  user-facing APIs under `crepe::api` (the folder structure should also reflect
-  this).
+
+  ```cpp
+  // Good
+  #include <iostream>
+  
+  #include "utils/helper.h"
+  
+  #include "main.h"
+  
+  // Bad
+  #include "main.h"
+  #include <iostream>
+  #include "utils/helper.h"
+  ```
+
+- When using libraries of which the header include order is important, make sure to separate the include statements using a blank line (clang-format may sort include statements, but does not sort across empty lines).
+
+  ```cpp
+  // Good
+  #include <iostream>
+  
+  #include <boost/algorithm/string.hpp>
+  
+  // Bad
+  #include <iostream>
+  #include <boost/algorithm/string.hpp>
+  ```
+
+- All engine-related code is implemented under the `crepe` namespace, user-facing APIs under `crepe::api` (the folder structure should also reflect this).
+
+
 - `using namespace` may not be used in header files, only in source files.
-- Do not (indirectly) include private *dependency* headers in API header files,
-  as these are no longer accessible when the engine is installed
-- Getter and setter functions are appropriately prefixed with `get_` and
-  `set_`.
-- Doxygen commands are used with a backslash instead of an at-sign (i.e.
-  `\brief` instead of `@brief`)
-- A singleton's instance is always accessed using a getter function that
-  instantiates its own class as a static variable within the getter function
-  scope, instead of storing the instance as a member variable directly:
+
+  ```cpp
+  // Good
+  // header.h
+  namespace crepe {
+      void init();
+  }
+  
+  // source.cpp
+  #include "header.h"
+  using namespace crepe;
+  void init() {}
+  
+  // Bad
+  // header.h
+  using namespace crepe;
+  void init();
+  ```
+
+- Do not (indirectly) include private *dependency* headers in API header files, as these are no longer accessible when the engine is installed
+
+  ```cpp
+  // Good
+  // api.h
+  namespace crepe::api {
+      void start();
+  }
+  
+  // Bad
+  // api.h
+  #include "private_dependency.h"
+  namespace crepe::api {
+      void start();
+  }
+  ```
+
+- Getter and setter functions are appropriately prefixed with `get_` and `set_`.
+
+  ```cpp
+  // Good
+  class Car {
+  public:
+      int get_speed() const;
+      void set_speed(int speed);
+  private:
+      int speed;
+  };
+  
+  // Bad
+  class Car {
+  public:
+      int speed() const;
+      void speed(int speed);
+  private:
+      int speed;
+  };
+  ```
+
+- Doxygen commands are used with a backslash instead of an at-sign (i.e. `\brief` instead of `@brief`)
+
+  ```cpp
+  // Good
+  /// \brief This function adds two numbers
+  int add(int a, int b);
+  
+  // Bad
+  /// @brief This function adds two numbers
+  int add(int a, int b);
+  ```
+
+- A singleton's instance is always accessed using a getter function that instantiates its own class as a static variable within the getter function scope, instead of storing the instance as a member variable directly:
 
   ```cpp
   class Bad {
-    static Bad instance;
-    Bad & get_instance() { return instance; }
+      static Bad instance;
+      Bad & get_instance() { return instance; }
   };
 
   class Good {
-    Good & get_instance() {
-      static Good instance;
-      return instance;
-    }
+      Good & get_instance() {
+          static Good instance;
+          return instance;
+      }
+  };
+  ```
+
+- Member variable default values should be directly defined in the class declaration instead of using the constructor.
+
+  ```cpp
+  // Good
+  class Car {
+  private:
+      int speed = 0;
+  };
+  
+  // Bad
+  class Car {
+  private:
+      int speed;
+      Car() : speed(0) {}
   };
   ```
-- Member variable default values should be directly defined in the class
-  declaration instead of using the constructor.
-- Header files declare either a single class or symbols within a single
-  namespace.
+
+- Header files declare either a single class or symbols within a single namespace.
+
+  ```cpp
+  // Good
+  // car.h
+  namespace crepe {
+      class Car {};
+  }
+  
+  // Bad
+  // car.h
+  namespace crepe {
+      class Car {};
+      class Engine {};
+  }
+  ```
+
 - Use of the `auto` type is not allowed, with the following exceptions:
   - When naming the item type in a range-based for loop
-  - When calling template factory methods that explicitly name the return type
-    in the function call signature
+  - When calling template factory methods that explicitly name the return type in the function call signature
   - When fetching a singleton instance
+
+  ```cpp
+  // Good
+  for (auto item : items) {}
+  
+  auto instance = Singleton::get_instance();
+  
+  // Bad
+  auto speed = car.get_speed();
+  ```
+
 - Only use member initializer lists for non-trivial types.
+
+  ```cpp
+  // Good
+  class Car {
+  public:
+      Car() : engine("V8") {}
+  private:
+      std::string engine;
+  };
+  
+  // Bad
+  class Car {
+  public:
+      Car() : speed(0) {}
+  private:
+      int speed;
+  };
+  ```
+
 - C++-style structs should define default values for all non-trivial fields.
-- Declare incomplete classes instead of including the relevant header where
-  possible (i.e. if you only need a reference or pointer type).
-- Template functions are only declared in a `.h` header, and defined in a
-  matching `.hpp` header.
-- Where possible, end (initializer) lists with a trailing comma (e.g. with
-  structs, enums)
+
+  ```cpp
+  // Good
+  struct Car {
+      std::string model = "Unknown";
+  };
+  
+  // Bad
+  struct Car {
+      std::string model;
+      Car() : model("Unknown") {}
+  };
+  ```
+
+- Declare incomplete classes instead of including the relevant header where possible (i.e. if you only need a reference or pointer type).
+
+  ```cpp
+  // Good
+  class Engine;
+  class Car {
+      Engine* engine;
+  };
+  
+  // Bad
+  #include "engine.h"
+  class Car {
+      Engine* engine;
+  };
+  ```
+
+- Template functions are only declared in a `.h` header, and defined in a matching `.hpp` header.
+
+  ```cpp
+  // Good
+  // add.h
+  template <typename T>
+  T add(T a, T b);
+  
+  // add.hpp
+  #include "add.h"
+  template <typename T>
+  T add(T a, T b) {
+      return a + b;
+  }
+  
+  // Bad
+  // add.h
+  template <typename T>
+  T add(T a, T b) {
+      return a + b;
+  }
+  ```
+
+- Where possible, end (initializer) lists with a trailing comma (e.g. with structs, enums)
+
+  ```cpp
+  // Good
+  enum Color {
+      Red,
+      Green,
+      Blue,
+  };
+  
+  // Bad
+  enum Color {
+      Red,
+      Green,
+      Blue
+  };
+  ```
 
 ## CMakeLists specific