Re: Weird string I/O problem

[stefan-lucks@see-the.signature]

On Wed, 3 Dec 2008, anon wrote:
> -- Build your own input routine.  Example:
[...]

if the variable Last is not initialised to 0 
   *before* you enter the loop ...

>   begin
>     Put ( P ) ;
>     input_string := ( others => nul ) ;
>     for index in input_string'Range loop   -- limits data size
>       Get ( char ) ;
>                                   -- Traps both LF or CR/LF type of EOL
>       exit when char = CR or char = LF ; 

... and if the user immediately presses the return key 
    (i.e., if you read an empty line), ...

>       input_string ( index ) := char ;
>       Last := Index ;  
>     end loop ;
>     if char = CR then  -- for CR/LF pairing type of OSs
>       Get ( char ) ;
>     end if ;
>     if char = LF or Last = input_string'Last then -- process EOL on screen
>       New_Line ;
>     end if ;
>     -- valid data is input_string ( 1 .. last ) ; 
>     -- with no term control characters like LF or CR

... then Input_String ( 1.. Last ) depends on 
    the uninitialised variable Last ...

>     return ( input_string ( 1 .. last ) ) ;

... and the statement above may raise an exception. 

>   end get ;

-- 
------ Stefan Lucks   --  Bauhaus-University Weimar  --   Germany  ------
               Stefan dot Lucks at uni minus weimar dot de
------  I  love  the  taste  of  Cryptanalysis  in  the  morning!  ------