Merge branch 'slides/185-simplify-extended-examples-within-the-subprograms-module' into 'master'

Resolve "Simplify Extended Examples within the Subprograms Module"

Closes #185

See merge request feng/training/material!257

Author: frank-at-adacore

courses/fundamentals_of_ada/070_subprograms.rst

@@ -42,6 +42,6 @@ Subprograms
 .. include:: 070_subprograms/07-function_specifics.rst
 .. include:: 070_subprograms/08-expression_functions.rst
 .. include:: 070_subprograms/09-potential_pitfalls.rst
-.. include:: 070_subprograms/10-extended_examples.rst
+.. include:: 070_subprograms/10-extended_example.rst
 .. include:: labs/070_subprograms.lab.rst
 .. include:: 070_subprograms/99-summary.rst

courses/fundamentals_of_ada/070_subprograms/10-extended_example.rst

@@ -0,0 +1,144 @@
+===================
+Extended Example
+===================
+
+-----------------------------
+Implementing a Simple "Set"
+-----------------------------
+
+* We want to indicate which colors of the rainbow are in a **set**
+
+   * If you remember from the *Basic Types* module, a type is made up of values and primitive operations
+
+* Our values will be
+
+   * Type indicating colors of the rainbow
+   * Type to group colors
+   * Mechanism to indicate which color is in our set
+
+* Our primitive operations will be
+
+   * Create a set
+   * Add a color to the set
+   * Remove a color from the set
+   * Check if color is in set
+
+--------------------
+Values for the Set
+--------------------
+
+* Colors of the rainbow
+
+   .. code:: Ada
+
+      type Color_T is (Red, Orange, Yellow, Green,
+                       Blue, Indigo, Violet,
+                       White, Black);
+
+* Group of colors
+
+   .. code:: Ada
+
+      type Group_Of_Colors_T is
+         array (Positive range <>) of Color_T;
+
+* Mechanism indicating which color is in the set
+
+   .. code:: Ada
+
+      type Set_T is array (Color_T) of Boolean;
+      --  if array component at Color is True,
+      --  the color is in the set
+
+----------------------------------
+Primitive Operations for the Set
+----------------------------------
+
+* Create a set
+
+   .. code:: Ada
+
+      function Make (Colors : Group_Of_Colors_T) return Set_T;
+
+* Add a color to the set
+
+   .. code:: Ada
+
+      procedure Add (Set    : in out Set_T;
+                     Color  :        Color_T);
+
+* Remove a color from the set
+
+   .. code:: Ada
+
+      procedure Remove (Set    : in out Set_T;
+                        Color  :        Color_T);
+
+* Check if color is in set
+
+   .. code:: Ada
+
+      function Contains (Set   : Set_T;
+                         Color : Color_T)
+                         return Boolean;
+
+--------------------------------------------
+Implementation of the Primitive Operations
+--------------------------------------------
+
+* Implementation of the primitives is easy
+
+   * We could do operations directly on :ada:`Set_T`, but that's not flexible
+
+.. code:: Ada
+
+   function Make (Colors : Group_Of_Colors_T) return Set_T is
+      Set : Set_T := (others => False);
+   begin
+      for Color of Colors loop
+         Set (Color) := True;
+      end loop;
+      return Set;
+   end Make;
+
+   procedure Add (Set   : in out Set_T;
+                  Color :        Color_T) is
+   begin
+      Set (Color) := True;
+   end Add;
+
+   procedure Remove (Set   : in out Set_T;
+                     Color :        Color_T) is
+   begin
+      Set (Color) := False;
+   end Remove;
+
+   function Contains (Set   : Set_T;
+                      Color : Color_T)
+                      return Boolean is
+      (Set (Color));
+
+-------------------------
+Using our Set Construct
+-------------------------
+
+.. code:: Ada
+
+   Rgb   : Set_T := Make ((Red, Green, Blue));
+   Light : Set_T := Make ((Red, Yellow, Green));
+
+.. code:: Ada
+
+   if Contains (Rgb, Black) then
+      Remove (Rgb, Black);
+   else
+      Add (Rgb, Black);
+   end if;
+
+*In addition, because of the operations available to arrays of Boolean, we can easily implement set operations*
+
+.. code:: Ada
+
+   Union         : Set_T := Rgb or Light;
+   Intersection  : Set_T := Rgb and Light;
+   Difference    : Set_T := Rgb xor Light;