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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Subject: Re: Is this my failure or of the compiler's debugger
Date: Wed, 11 Jan 2023 15:43:36 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <nnd$75982fc8$3d64f38c@635cdfb43e75a9fd>

On 2023-01-11 0:17, ldries46 wrote:
> Op 10-1-2023 om 19:12 schreef Niklas Holsti:
>> On 2023-01-10 15:16, ldries46 wrote:
>>> I try to create a program that read Unbounded strings from a file in 
>>> the loop:
>>>        Open(C_File, In_File, To_String(Inp_File));
>>>        while not End_of_File(C_File) loop
>>>           str_line_n := To_Unbounded_String(Get_Line(C_File));
>>>           Buffer_GL.Set_Buffer(str_line_n); -- breakpoint on this line
>>>           glade_lines := glade_lines + 1;
>>>        end loop;
>>>        Close(C_File);
>>> where str_line_n is of the type Unbounded_String.
>>> I used a test file with the below presented three text lines:
>>> Line 1 abcdef9876543210
>>> Line 2 " abcdef"9876543210
>>> Line 3 "abc"de"f"9876543210
>>> In the debugger the results were:
>>> "Line 1 abcdef 9876543210"
>>> "Line 2 "" abcdef"" 98765432"
>>> "Line 3 ""abc""de ""f""987654"
>> It seems that the debugger displays the strings in the form of Ada 
>> string literals, which are enclosed in quotes (") and within which 
>> each quote character has to be duplicated (to show that it is not the 
>> terminating quote). So the duplication of the quotes is nothing to 
>> worry about. If you were to print out the strings (with Ada.Text_IO) 
>> they should appear just as in the input, with only the original quote 
>> characters.
>> However, your example also shows some extra blank spaces in the 
>> debugger output, for example:
>> Input   : Line 1 abcdef9876543210
>> Debugger: "Line 1 abcdef 9876543210"
> Not only that but also some of the  last characters disappear in line 2 
> the 10 and in line 3 3210

My guess is that these differences are bugs in the debugger's display of 
strings with embedded quote characters. For Line 1, which has no 
embedded quotes, the full string is displayed (though with an inserted 
blank). For Line 2, with two embedded quotes, two of the last characters 
are not displayed. For Line 3, with four embedded quotes, four of the 
last characters are not displayed. It seems that the debugger does not 
realize that doubling the quote characters makes the displayed string 

Try to print the strings with Ada.Text_IO instead, that should give the 
right result. In other words, your code reading the strings works, but 
the debugger is probably buggy. (One reason why I avoid debuggers 
whenever I can.)

  parent reply	other threads:[~2023-01-11 13:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <nnd$70b29fcd$4811e339@5bc1ef990a7003a8>
2023-01-10 18:12 ` Is this my failure or of the compiler's debugger Niklas Holsti
2023-01-10 22:17   ` ldries46
2023-01-11  7:40     ` ldries46
2023-01-11 13:43     ` Niklas Holsti [this message]
2023-01-11 16:52       ` ldries46
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