Resolve "Array chapter improvements"

Author: frank-at-adacore

courses/fundamentals_of_ada/050_array_types/02-constrained_array_types.rst

@@ -6,146 +6,34 @@ Constrained Array Types
 Constrained Array Type Declarations
 -------------------------------------
 
-* Syntax
+Syntax (simplified)
 
-      .. code:: Ada
-
-         constrained_array_definition ::=
-            array index_constraint of subtype_indication
-         index_constraint ::= (discrete_subtype_definition
-            {, discrete_subtype_indication})
-         discrete_subtype_definition ::=
-            discrete_subtype_indication | range
-         subtype_indication ::= subtype_mark [constraint]
-         range ::= range_attribute_reference |
-            simple_expression .. simple_expression
-
-* Examples
+.. container:: latex_environment footnotesize
 
    .. code:: Ada
 
-      type Full_Week_T is array (Days) of Float;
-      type Work_Week_T is array (Days range Mon .. Fri) of Float;
-      type Weekdays is array (Mon .. Fri) of Float;
-      type Workdays is array (Weekdays'Range) of Float;
-
-----------------------------------
-Multiple-Dimensioned Array Types
-----------------------------------
-
-.. container:: columns
-
- .. container:: column
-
-    * Declared with more than one index definition
-
-       - Constrained array types
-       - Unconstrained array types
-
-    * Components accessed by giving value for each index
-
- .. container:: column
-
-   .. container:: latex_environment small
-
-    .. code:: Ada
-
-       type Three_Dimensioned is
-         array (
-           Boolean,
-           12 .. 50,
-           Character range 'a' .. 'z')
-           of Integer;
-         TD : Three_Dimensioned;
-         ...
-       begin
-         TD (True, 42, 'b') := 42;
-         TD (Flag, Count, Char) := 42;
-
------------------------------
-Tic-Tac-Toe Winners Example
------------------------------
-
-.. container:: columns
-
- .. container:: column
-
-    .. code:: Ada
-
-       -- 9 positions on a board
-       type Move_Number is range 1 .. 9;
-       -- 8 ways to win
-       type Winning_Combinations is
-          range 1 .. 8;
-       -- need 3 positions to win
-       type Required_Positions is
-          range 1 .. 3;
-       Winning : constant array (
-          Winning_Combinations,
-          Required_Positions)
-          of Move_Number := (1 => (1,2,3),
-                             2 => (1,4,7),
-                             ...
-
- .. container:: column
-
-    .. list-table::
-       :width: 55%
-
-      * - :superscript:`1` **X**
-
-        - :superscript:`2` **X**
-        - :superscript:`3` **X**
-
-      * - :superscript:`4`
-
-        - :superscript:`5`
-        - :superscript:`6`
-
-      * - :superscript:`7`
+      type <typename> is array (<index constraint>) of <constrained type>;
 
-        - :superscript:`8`
-        - :superscript:`9`
+where
 
-      * -
+.. container:: latex_environment quote
 
-        -
-        -
+      **typename** - identifier
 
-      * - :superscript:`1` **X**
+      **index constraint** - discrete range or type
 
-        - :superscript:`2`
-        - :superscript:`3`
+      **constrained type** - type with size known at compile time
 
-      * - :superscript:`4` **X**
+Examples
 
-        - :superscript:`5`
-        - :superscript:`6`
+.. container:: latex_environment footnotesize
 
-      * - :superscript:`7` **X**
-
-        - :superscript:`8`
-        - :superscript:`9`
-
-      * -
-
-        -
-        -
-
-      * - :superscript:`1` **X**
-
-        - :superscript:`2`
-        - :superscript:`3`
-
-      * - :superscript:`4`
-
-        - :superscript:`5` **X**
-        - :superscript:`6`
-
-      * - :superscript:`7`
+   .. code:: Ada
 
-        - :superscript:`8`
-        - :superscript:`9` **X**
+      type Integer_Array_T is array (1 .. 3) of Integer;
+      type Boolean_Array_T is array (Boolean) of Integer;
+      type Character_Array_T is array (character range 'a' .. 'z') of Boolean;
+      type Copycat_T is array (Boolean_Array_T'Range) of Integer;
 
 ------
 Quiz

courses/fundamentals_of_ada/050_array_types/03-unconstrained_array_types.rst

@@ -48,6 +48,7 @@ Supplying Index Constraints for Objects
       .. code:: Ada
 
          Weekend : Schedule := (Sat => 4.0, Sun => 0.0);
+         -- (Note this is an array aggregate, explained later)
 
    - Further type definitions (shown later)
    - Actual parameter to subprogram (shown later)
@@ -232,77 +233,27 @@ Quiz
 
 .. code:: Ada
 
-   type Array_T is array (Integer range <>) of Integer;
-   subtype Array1_T is Array_T (1 .. 4);
-   subtype Array2_T is Array_T (0 .. 3);
-   X : Array_T  := (1, 2, 3, 4);
-   Y : Array1_T := (1, 2, 3, 4);
-   Z : Array2_T := (1, 2, 3, 4);
+   type Bit_T is range 0 .. 1;
+   type Bit_Array_T is array (Positive range <>) of Bit_T;
 
 .. container:: columns
 
  .. container:: column
 
-   Which statement(s) is (are) legal?
+   Which declaration(s) is (are) legal?
 
-   A. ``X (1) := Y (1);``
-   B. :answermono:`Y (1) := Z (1);`
-   C. :answermono:`Y := X;`
-   D. :answermono:`Z := X;`
+   A. ``AAA : Array_T (0..99);``
+   B. :answermono:`BBB : Array_T (1..32);`
+   C. :answermono:`CCC : Array_T (17..16);`
+   D. ``DDD : Array_T;``
 
  .. container:: column
 
   .. container:: animate
 
    Explanations
 
-   A. :ada:`Array_T` starts at :ada:`Integer'First` not :ada:`1`
-   B. OK, both in range
-   C. OK, same type and size
-   D. OK, same type and size
-
-------
-Quiz
-------
-
-.. code:: Ada
-
-    type My_Array is array (Boolean range <>) of Boolean;
-
-    O : My_Array (False .. False) := (others => True);
-
-What is the value of :ada:`O (True)`?
-
-A. :ada:`False`
-B. :ada:`True`
-C. None: Compilation error
-D. :answer:`None: Run-time error`
-
-.. container:: animate
-
-    :ada:`True` is not a valid index for :ada:`O`.
-
-    NB: GNAT will emit a warning by default.
-
-------
-Quiz
-------
-
-.. code:: Ada
-
-    type My_Array is array (Positive range <>) of Boolean;
-
-    O : My_Array (0 .. -1) := (others => True);
-
-What is the value of :ada:`O'Length`?
-
-A. 1
-B. :answer:`0`
-C. None: Compilation error
-D. None: Run-time error
-
-.. container:: animate
-
-    When the upper bound is less than the lower bound, this is an empty array.
-    For empty arrays, the index can be out of range for the index type.
-
+   A. :ada:`Array_T` index is :ada:`Positive` which starts at 1
+   B. OK, indices are in range
+   C. OK, indicates a zero-length array
+   D. Object must be constrained

courses/fundamentals_of_ada/050_array_types/05-operations.rst

@@ -20,15 +20,29 @@ Object-Level Operations
 
 * Conversions
 
-   .. code:: Ada
-
-      C := Foo (B);
-
    - Component types must be the same type
    - Index types must be the same or convertible
    - Dimensionality must be the same
    - Bounds must be compatible (not necessarily equal)
 
+   .. code:: Ada
+
+      declare
+         type Index1_T is range 1 .. 2;
+         type Index2_T is range 101 .. 102;
+         type Array1_T is array (Index1_T) of Integer;
+         type Array2_T is array (Index2_T) of Integer;
+         type Array3_T is array (Boolean) of Integer;
+
+         One   : Array1_T;
+         Two   : Array2_T;
+         Three : Array3_T;
+
+      begin
+
+         One := Array1_T (Two);    -- OK
+         Two := Array2_T (Three);  -- Illegal (indices not convertible)
+
 -------------------------------
 Extra Object-Level Operations
 -------------------------------
@@ -142,23 +156,23 @@ Quiz
 
    type Index_T is range 1 .. 10;
    type OneD_T is array (Index_T) of Boolean;
-   type ThreeD_T is array (Index_T, Index_T, Index_T) of OneD_T;
-   A : ThreeD_T;
+   type TwoD_T is array (Index_T) of OneD_T;
+   A : TwoD_T;
    B : OneD_T;
 
 Which statement(s) is (are) legal?
 
-   A. :answermono:`B(1) := A(1,2,3)(1) or A(4,3,2)(1);`
-   B. :answermono:`B := A(2,3,4) and A(4,3,2);`
-   C. ``A(1,2,3..4) := A(2,3,4..5);``
+   A. :answermono:`B(1) := A(1,2) or A(4,3);`
+   B. :answermono:`B := A(2) and A(4);`
+   C. ``A(1..2)(4) := A(5..6)(8);``
    D. :answermono:`B(3..4) := B(4..5)`
 
 .. container:: animate
 
    Explanations
 
-   A. All three objects are just Boolean values
+   A. All objects are just Boolean values
    B. An element of :ada:`A` is the same type as :ada:`B`
-   C. No slicing of multi-dimensional arrays
+   C. Slice must be of outermost array
    D. Slicing allowed on single-dimension arrays