--  C457002.A
--
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--     The ACAA has created and maintains the Ada Conformity Assessment Test
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--     assessment of a language processor. This test suite should not be used
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--*
--  OBJECTIVE:
--     Check that for the evaluation of a boolean if expression, the condition
--     specified after if, and any conditions specified after elsif, are
--     evaluated in succession, until one evaluates to True or all conditions
--     are evaluated and yield False.
--
--     Check that result of a boolean if expression is the result of
--     evaluating the dependent expression corresponding to the condition that
--     evaluates to True; or True if all of the conditions evaluate to False.
--
--  HISTORY:
--     BJM 12/28/11  Created original test.
--     RLB  3/24/14  Changed name and added missing objective.
--     RLB  4/24/14  Corrected error in objective.
--!

with Report; use Report;

procedure C457002 is

   Last_Check           : Natural := Natural'First;
   Expression_Evaluated : Boolean := False;

   function Evaluation_Check (X : Boolean) return Boolean is
   begin
      if Expression_Evaluated then
         Failed ("More than one dependent expression evaluated");
      end if;

      Expression_Evaluated := True;
      return X;
   end Evaluation_Check;

   function Succession_Check (X : Integer; Result : Boolean) return Boolean is
   begin
      if Natural'Succ (Last_Check) /= X then
         Failed ("Expression evaluated out of order");
      end if;

      Last_Check := X;
      return Result;
   end Succession_Check;

begin
   Test
     ("C457002",
      "Check that for the evaluation of a Boolean " &
      "if expression, the condition specified after if, " &
      "and any conditions specified after elsif, are " &
      "evaluated in succession, until one evalues to True " &
      "or all conditions are evaluated and yield false");

   declare
      Expression_Value : Boolean := False;
   begin

      --  All conditions are evaluated, and executes the else
      Expression_Value :=
        (if Succession_Check (1, False) then Evaluation_Check (False)
         elsif Succession_Check (2, False) then Evaluation_Check (False)
         elsif Succession_Check (3, False) then Evaluation_Check (False)
         else Evaluation_Check (True));

      if not Expression_Value then
         Failed ("Unexpected value for conditional expression - 1");
      end if;

      if Last_Check /= 3 then
         Failed ("Unexpected value for last evaluated expression - 1");
      end if;

   exception
      when others =>
         Failed ("Unexpected exception raised - 1");
   end;

   Last_Check           := Natural'First;
   Expression_Evaluated := False;

   declare
      Expression_Value : Boolean := True;
   begin

      --  All conditions are evaluated, no else specified
      Expression_Value :=
        (if Succession_Check (1, False) then Evaluation_Check (False)
         elsif Succession_Check (2, False) then Evaluation_Check (False)
         elsif Succession_Check (3, False) then Evaluation_Check (False));

      if not Expression_Value then
         Failed ("Unexpected value for conditional expression - 2");
      end if;

      if Last_Check /= 3 then
         Failed ("Unexpected value for last evaluated expression - 2");
      end if;

   exception
      when others =>
         Failed ("Unexpected exception raised - 2");
   end;

   Last_Check           := Natural'First;
   Expression_Evaluated := False;

   declare
      Expression_Value : Boolean := False;
   begin

      --  All conditions evaluated up to second elsif
      Expression_Value :=
        (if Succession_Check (1, False) then Evaluation_Check (False)
         elsif Succession_Check (2, False) then Evaluation_Check (False)
         elsif Succession_Check (3, True) then Evaluation_Check (True)
         else Evaluation_Check (False));

      if not Expression_Value then
         Failed ("Unexpected value for conditional expression - 3");
      end if;

      if Last_Check /= 3 then
         Failed ("Unexpected value for last evaluated expression - 3");
      end if;

   exception
      when others =>
         Failed ("Unexpected exception raised - 3");
   end;

   Last_Check           := Natural'First;
   Expression_Evaluated := False;

   declare
      Expression_Value : Boolean := False;
   begin

      --  All conditions evaluated up to second elsif, no else specified
      Expression_Value :=
        (if Succession_Check (1, False) then Evaluation_Check (False)
         elsif Succession_Check (2, False) then Evaluation_Check (False)
         elsif Succession_Check (3, True) then Evaluation_Check (True));

      if not Expression_Value then
         Failed ("Unexpected value for conditional expression - 4");
      end if;

      if Last_Check /= 3 then
         Failed ("Unexpected value for last evaluated expression - 4");
      end if;

   exception
      when others =>
         Failed ("Unexpected exception raised - 4");
   end;

   Last_Check           := Natural'First;
   Expression_Evaluated := False;

   declare
      Expression_Value : Boolean := False;
   begin

      --  All conditions evaluated up to first elsif
      Expression_Value :=
        (if Succession_Check (1, False) then Evaluation_Check (False)
         elsif Succession_Check (2, True) then Evaluation_Check (True)
         elsif Succession_Check (3, False) then Evaluation_Check (False)
         else Evaluation_Check (False));

      if not Expression_Value then
         Failed ("Unexpected value for conditional expresion - 5");
      end if;

      if Last_Check /= 2 then
         Failed ("Unexpected value for last evaluated expression - 5");
      end if;

   exception
      when others =>
         Failed ("Unexpected exception raised - 5");
   end;

   Last_Check           := Natural'First;
   Expression_Evaluated := False;

   declare
      Expression_Value : Boolean := False;
   begin

      --  Only the if condition is evaluated
      Expression_Value :=
        (if Succession_Check (1, True) then Evaluation_Check (True)
         elsif Succession_Check (2, True) then Evaluation_Check (False)
         elsif Succession_Check (3, True) then Evaluation_Check (False)
         else Evaluation_Check (False));

      if not Expression_Value then
         Failed ("Unexpected value for conditional expression - 6");
      end if;

      if Last_Check /= 1 then
         Failed ("Unexpected value for last evaluated expression - 6");
      end if;

   exception
      when others =>
         Failed ("Unexpected exception raised - 6");
   end;

   Result;
end C457002;