HELP ! Problems with Get and Put in Generic Procedure

HELP ! Problems with Get and Put in Generic Procedure

[Tanya]

I am having problems compiling a program that uses a generic GetData
procedure.  Inside this procedure I try to Get data from the keyboard
and store into an array.  My generic specification and body both
compile fine...but when I try to instantiate the generic procedure in
the main driver, I get errors:
"procedure or entry name expected" and "expect valid subprogram name
in renaming".  What am I doing wrong ??  I can't find any examples of
how to do this.  Any help would be greatly appreciated !!!  Thanks !

Here is my program:

(generic spec file)  ******************************************

 GENERIC
      
      TYPE ElementType IS PRIVATE;         -- any nonlimited type
      TYPE IndexType IS ( <> );            -- any discrete type for
                                           -- index value
      TYPE ArrayType IS ARRAY (IndexType RANGE <>) OF ElementType;
      
      WITH PROCEDURE Read (Item : IN ElementType);
      
   PROCEDURE Get_Array_Generic (List : IN OUT ArrayType);
   -- Input : Array type and input file stream.
   -- Action: Will read in elements and store in array.
   -- Output: Array filled with elements.


(generic body file)  ********************************************

PROCEDURE Get_Array_Generic (List : IN OUT ArrayType) IS
   -------------------------------------------------------------------
   -- Input : Array type and input file stream.
   -- Action: Will read in elements and store in array.
   -- Output: Array filled with elements.
   -------------------------------------------------------------------
   
      Index : IndexType;
      Element : ElementType;
      
   BEGIN  -- Get_Array_Generic
      
      Index := List'Last;               -- initialize array index to
                                        -- first subscript
      
      FOR Index IN List'RANGE LOOP
                     
            Read (Item => Element);        -- read elements into array
         
         -- store data into the array
         
            List (Index) := Element;
         
         END LOOP;
 
   END Get_Array_Generic;


(Main driver )  ********************************************


WITH Ada.Text_IO;
USE Ada.Text_IO;
WITH Ada.Integer_Text_IO;
USE Ada.Integer_Text_IO;


PROCEDURE Generic_Test IS
----------------------------------------------------------------------
-- Input : None
-- Action: 
-- Output: None                                    
----------------------------------------------------------------------

   MaxInt : CONSTANT Integer := 10;
   SUBTYPE IntegerRange IS Integer RANGE 1..MaxInt;
   TYPE Integer_Array IS ARRAY (IntegerRange RANGE <>) OF Integer;
      

  ***  This is where I am having problems (in the instantiation)  ***


   PROCEDURE GetIntegers IS NEW Get_Array_Generic
      (ElementType => Integer,
       IndexType => IntegerRange,
       ArrayType => Integer_Array,
       Read => Ada.Integer_Text_IO);
       
   
   IntArray : Integer_Array(IntegerRange);
   
   TargetInteger : Integer;

BEGIN  -- Generic_Test
   
   Ada.Text_IO.Put (Item => "Please enter ");
   Ada.Integer_Text_IO.Put (Item => MaxInt, Width => 2);
   Ada.Text_IO.Put (Item => " integer values: ");
   Ada.Text_IO.New_Line;  

   GetIntegers (List => IntArray);
  
END Generic_Test;

Re: HELP ! Problems with Get and Put in Generic Procedure

[Robert I. Eachus]

Tanya wrote:
> I am having problems compiling a program that uses a generic GetData
> procedure.  Inside this procedure I try to Get data from the keyboard
> and store into an array.  My generic specification and body both
> compile fine...but when I try to instantiate the generic procedure in
> the main driver, I get errors:
> "procedure or entry name expected" and "expect valid subprogram name
> in renaming".  What am I doing wrong ??  I can't find any examples of
> how to do this.  Any help would be greatly appreciated !!!  Thanks !
> 
> Here is my program:
> 
> (generic spec file)  ******************************************
> 
>  GENERIC
>       
>       TYPE ElementType IS PRIVATE;         -- any nonlimited type
>       TYPE IndexType IS ( <> );            -- any discrete type for
>                                            -- index value
>       TYPE ArrayType IS ARRAY (IndexType RANGE <>) OF ElementType;
>       
>       WITH PROCEDURE Read (Item : IN ElementType);
>       
>    PROCEDURE Get_Array_Generic (List : IN OUT ArrayType);
>    -- Input : Array type and input file stream.
>    -- Action: Will read in elements and store in array.
>    -- Output: Array filled with elements.
> 
> 
> (generic body file)  ********************************************
> 
> PROCEDURE Get_Array_Generic (List : IN OUT ArrayType) IS
>    -------------------------------------------------------------------
>    -- Input : Array type and input file stream.
>    -- Action: Will read in elements and store in array.
>    -- Output: Array filled with elements.
>    -------------------------------------------------------------------
>    
>       Index : IndexType;
>       Element : ElementType;
>       
>    BEGIN  -- Get_Array_Generic
>       
>       Index := List'Last;               -- initialize array index to
>                                         -- first subscript
>       
>       FOR Index IN List'RANGE LOOP
>                      
>             Read (Item => Element);        -- read elements into array
>          
>          -- store data into the array
>          
>             List (Index) := Element;
>          
>          END LOOP;
>  
>    END Get_Array_Generic;
> 
> 
> (Main driver )  ********************************************
> 
> 
> WITH Ada.Text_IO;
> USE Ada.Text_IO;
> WITH Ada.Integer_Text_IO;
> USE Ada.Integer_Text_IO;
> 
> 
> PROCEDURE Generic_Test IS
> ----------------------------------------------------------------------
> -- Input : None
> -- Action: 
> -- Output: None                                    
> ----------------------------------------------------------------------
> 
>    MaxInt : CONSTANT Integer := 10;
>    SUBTYPE IntegerRange IS Integer RANGE 1..MaxInt;
>    TYPE Integer_Array IS ARRAY (IntegerRange RANGE <>) OF Integer;
>       
> 
>   ***  This is where I am having problems (in the instantiation)  ***
> 
> 
>    PROCEDURE GetIntegers IS NEW Get_Array_Generic
>       (ElementType => Integer,
>        IndexType => IntegerRange,
>        ArrayType => Integer_Array,
>        Read => Ada.Integer_Text_IO);
-- This is the problem. You need a procedure here not a package name. 

>    
>    IntArray : Integer_Array(IntegerRange);
>    
>    TargetInteger : Integer;
> 
> BEGIN  -- Generic_Test
>    
>    Ada.Text_IO.Put (Item => "Please enter ");
>    Ada.Integer_Text_IO.Put (Item => MaxInt, Width => 2);
>    Ada.Text_IO.Put (Item => " integer values: ");
>    Ada.Text_IO.New_Line;  
> 
>    GetIntegers (List => IntArray);
>   
> END Generic_Test;

But Read => Ada.Integer_Text_IO.Read won't work because the parameter 
profile doesn't match Get or Put.  You can change your generic to match, 
or put a "wrapper" around Ada.Text_IO.Get.  (But remember that in and 
out are part of the profile.)

For those of you who worry about helping students too much, I think this 
  is a tricky enough issue to justify this amount of help. (I suspect 
that Tanya first tried with Read => Ada.Integer_Text_IO.Get.) If this 
doesn't get Tanya over the hump, she can ask her instructor or TA.

-- 

                                                  Robert I. Eachus

�In an ally, considerations of house, clan, planet, race are 
insignificant beside two prime questions, which are: 1. Can he shoot? 2. 
Will he aim at your enemy?� -- from the Laiden novels by Sharon Lee and 
Steve Miller.

Re: HELP ! Problems with Get and Put in Generic Procedure

[Jeffrey Carter]

Tanya wrote:

R. Eachus addressed your question, but there's another likely 
misunderstanding on your part I'd like to mention.

> 
> (generic spec file)  ******************************************
> 
>  GENERIC
>       
>       TYPE ElementType IS PRIVATE;         -- any nonlimited type
>       TYPE IndexType IS ( <> );            -- any discrete type for
>                                            -- index value
>       TYPE ArrayType IS ARRAY (IndexType RANGE <>) OF ElementType;
>       
>       WITH PROCEDURE Read (Item : IN ElementType);

Mode "in" seems odd for a procedure named Read.

>       
>    PROCEDURE Get_Array_Generic (List : IN OUT ArrayType);
>    -- Input : Array type and input file stream.
>    -- Action: Will read in elements and store in array.
>    -- Output: Array filled with elements.
> 
> 
> (generic body file)  ********************************************
> 
> PROCEDURE Get_Array_Generic (List : IN OUT ArrayType) IS
>    -------------------------------------------------------------------
>    -- Input : Array type and input file stream.
>    -- Action: Will read in elements and store in array.
>    -- Output: Array filled with elements.
>    -------------------------------------------------------------------
>    
>       Index : IndexType;
>       Element : ElementType;
>       
>    BEGIN  -- Get_Array_Generic
>       
>       Index := List'Last;               -- initialize array index to
>                                         -- first subscript

This assignment is the only place this variable is mentioned in this 
procedure. Since you're not doing anything with it, why not eliminate it?

>       
>       FOR Index IN List'RANGE LOOP
>                      
>             Read (Item => Element);        -- read elements into array
>          
>          -- store data into the array
>          
>             List (Index) := Element;
>          
>          END LOOP;
>  
>    END Get_Array_Generic;

Your code will look better to most of us if you use all lower case for 
reserved words, and use underlines instead of case to separate words in 
identifiers (Index_Type, not IndexType).

-- 
Jeff Carter
"It's all right, Taggart. Just a man and a horse being hung out there."
Blazing Saddles

Re: HELP ! Problems with Get and Put in Generic Procedure

[Richard Riehle]

I am including Tanya's message at the end of this reply.

It is usually a design error to include the I/O capabilities in
a generic  component.  It is a matter of loose coupling.   Separate
out the I/O portion of your design from the generic component.  Add
iterators to the component if you to traverse the entire entity.  You
can also add a current_item indicator to your component so you will
be able to write a method to fill and clear the array one item at a
time with an external procedure.

Richard Riehle

----------------------------------------------------------------------------

Tanya wrote:

> I am having problems compiling a program that uses a generic GetData
> procedure.  Inside this procedure I try to Get data from the keyboard
> and store into an array.  My generic specification and body both
> compile fine...but when I try to instantiate the generic procedure in
> the main driver, I get errors:
> "procedure or entry name expected" and "expect valid subprogram name
> in renaming".  What am I doing wrong ??  I can't find any examples of
> how to do this.  Any help would be greatly appreciated !!!  Thanks !
>
> Here is my program:
>
> (generic spec file)  ******************************************
>
>  GENERIC
>
>       TYPE ElementType IS PRIVATE;         -- any nonlimited type
>       TYPE IndexType IS ( <> );            -- any discrete type for
>                                            -- index value
>       TYPE ArrayType IS ARRAY (IndexType RANGE <>) OF ElementType;
>
>       WITH PROCEDURE Read (Item : IN ElementType);
>
>    PROCEDURE Get_Array_Generic (List : IN OUT ArrayType);
>    -- Input : Array type and input file stream.
>    -- Action: Will read in elements and store in array.
>    -- Output: Array filled with elements.
>
> (generic body file)  ********************************************
>
> PROCEDURE Get_Array_Generic (List : IN OUT ArrayType) IS
>    -------------------------------------------------------------------
>    -- Input : Array type and input file stream.
>    -- Action: Will read in elements and store in array.
>    -- Output: Array filled with elements.
>    -------------------------------------------------------------------
>
>       Index : IndexType;
>       Element : ElementType;
>
>    BEGIN  -- Get_Array_Generic
>
>       Index := List'Last;               -- initialize array index to
>                                         -- first subscript
>
>       FOR Index IN List'RANGE LOOP
>
>             Read (Item => Element);        -- read elements into array
>
>          -- store data into the array
>
>             List (Index) := Element;
>
>          END LOOP;
>
>    END Get_Array_Generic;
>
> (Main driver )  ********************************************
>
> WITH Ada.Text_IO;
> USE Ada.Text_IO;
> WITH Ada.Integer_Text_IO;
> USE Ada.Integer_Text_IO;
>
> PROCEDURE Generic_Test IS
> ----------------------------------------------------------------------
> -- Input : None
> -- Action:
> -- Output: None
> ----------------------------------------------------------------------
>
>    MaxInt : CONSTANT Integer := 10;
>    SUBTYPE IntegerRange IS Integer RANGE 1..MaxInt;
>    TYPE Integer_Array IS ARRAY (IntegerRange RANGE <>) OF Integer;
>
>
>   ***  This is where I am having problems (in the instantiation)  ***
>
>    PROCEDURE GetIntegers IS NEW Get_Array_Generic
>       (ElementType => Integer,
>        IndexType => IntegerRange,
>        ArrayType => Integer_Array,
>        Read => Ada.Integer_Text_IO);
>
>
>    IntArray : Integer_Array(IntegerRange);
>
>    TargetInteger : Integer;
>
> BEGIN  -- Generic_Test
>
>    Ada.Text_IO.Put (Item => "Please enter ");
>    Ada.Integer_Text_IO.Put (Item => MaxInt, Width => 2);
>    Ada.Text_IO.Put (Item => " integer values: ");
>    Ada.Text_IO.New_Line;
>
>    GetIntegers (List => IntArray);
>
> END Generic_Test;