Re:I'm baffled...

Re:I'm baffled...

[ANH_VO]

I am afraid that more codes need to be posted in order for me at least to find
out what is going on. In fact, it is not easy to reproduce the Constraint_Error
without knowing the exact Word_List.

Anh Vo

____________________Reply Separator____________________
Subject:    I'm baffled...
Author: Wes Groleau <wwgrol@sparc01.ftw.rsc.raytheon.com>
Date:       10/30/01 5:16 PM


Probably something simple, but I don't see it ....

I don't think it's a compiler bug because
I get the same error from Apex that I get from GNAT.

But how can I get a constraint_error on line 166
of ada.strings.maps?  That line is:
   Identity : constant Character_Mapping :=

I can't get either debugger to let me examine things
in the run-time.

Code excerpt:

   package ASF renames Ada.Strings.Fixed;
   package AS renames Ada.Strings;

   function Position_Of (Pattern : String) return Index is

      Result : Index := 47;
      -- just to make it any old legal value

      Checkpoint : Character := 'A';

   begin
      Checkpoint := 'B';
      Result := ASF.Index
                (Source  => Word_List (Current_Index + 1 ..
Word_List'Last),
                 Pattern => Pattern,
                 Going   => AS.Forward );
      Checkpoint := 'C';
      
      if Result /= 0 then
      Checkpoint := 'D';
         return Result;
      else
      Checkpoint := 'E';
         return ASF.Index
                (Source  => Word_List ( Word_List'First .. Current_Index
- 1),
                 Pattern => Pattern,
                 Going   => AS.Backward );
      Checkpoint := 'F';
      end if;
      Checkpoint := 'G';

   exception
      when E : others =>
        Ada.Text_IO.Put_Line (Ada.Exceptions.Exception_Information(E));
        Ada.Text_IO.Put_Line ("Checkpoint    => " & Checkpoint);
        Ada.Text_IO.Put_Line ("Context       => " & Word_List
(Current_Index - 10 .. Current_Index + 10) );
        Ada.Text_IO.Put_Line ("Pattern       => " & Pattern);
        Ada.Text_IO.Put_Line ("Current_Index => " & Integer'Image
(Current_Index));
        Ada.Text_IO.Put_Line ("Result        => " & Integer'Image
(Result));

      raise;

   end Position_Of;

Typical error output:

Exception name: CONSTRAINT_ERROR
Message: a-strmap.ads:166

Checkpoint    => B
Context       => addenda addendum adhe
Pattern       =>  pri
Current_Index =>  117947
Result        =>  47

(Word_List is a BIG string)

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau
_______________________________________________

Re:I'm baffled...

[ANH_VO]

On second thought, I could duplicate the problem providing one confirmation. Is
Index type, returned by function Position_Of, look like? It must NOT be Natural.

A. Vo

I am afraid that more codes need to be posted in order for me at least to find
out what is going on. In fact, it is not easy to reproduce the Constraint_Error
without knowing the exact Word_List.

Anh Vo

Re: I'm baffled...

[Wes Groleau]

ANH_VO@udlp.com wrote:
> 
> On second thought, I could duplicate the problem providing one confirmation. Is
> Index type, returned by function Position_Of, look like? It must NOT be Natural.
> 
> A. Vo
> 
> I am afraid that more codes need to be posted in order for me at least to find
> out what is going on. In fact, it is not easy to reproduce the Constraint_Error
> without knowing the exact Word_List.
> 
> Anh Vo

oops, sorry for the omission.

  word_list : constant String := "any VERY long string " & 
                                 "with spaces every four " & 
                                 "to fifteen characters";

  subtype index is positive range word_list'range;

current_index jumps around but is always in index

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau

Re: I'm baffled...

[Wes Groleau]

ANH_VO@udlp.com wrote:
> 
> On second thought, I could duplicate the problem providing one confirmation. Is
> Index type, returned by function Position_Of, look like? It must NOT be Natural.

Thanks, that was it.  Changed it to Integer and the error went away.

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau