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From: John English <je@bton.ac.uk>
Subject: Re: CONTRAINT ERROR (was Re: parsing a string)
Date: 2000/01/26
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Date: 2000-01-26T13:46:16+00:00
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pumilia@est.it wrote:
> Here is my test procedure, aimed to converting an unbounded string
> to string and then to parse the string:
> 
> -- str2_test --------------------------------------
> [...snip...]
> procedure str2_test is
> 
>  output_file_string : unbounded_string ;
>  output_file : string (1..25) ;
>  pos1 : natural;
> 
> Begin
> 
>     get_line(output_file_string);
> 
>    put(" output:  "); put(output_file_string); put("<--"); new_line;
>    output_file :=  to_string(output_file_string);

Output_String is exactly 25 characters long, so Output_File_String
has to be exactly 25 characters long too. If it isn't, you'll get
a Constraint_Error, just as you discovered.

Try this:
  if Length(Output_File_String) > 25 then
    Output_File := To_String(Output_File_Length)(1..25);
  else
    Output_File := (others => ' ');  -- to pad result with spaces
    Output_File(1..Length(Output_File_String)) :=
                   To_String(Output_File_Length);
  end if;

(untested, and would be better with the aid of Output_File'Length,
Output_File'First and Output_File'Last instead of magic numbers 1
and 25.)

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