Accented characters in concatenated strings

[Roland57]

Hello!

I try to display accented characters in a Windows console program. When the string is concatenated to another, the accented characters isn't displayed correctly. Why ?

Here is my code. I compiled it with FPC 3.0.0.

Code: Pascal  [Select][+][-]

1. begin
2.   WriteLn('r'#130'pertoire');
3.   WriteLn('r'#130'pertoir' + 'e');
4. end.

[engkin]

Code: Pascal  [Select][+][-]

1. {$codepage UTF8}
2.  
3. begin
4.   WriteLn('répertoire');
5.   WriteLn('répertoir' + 'e');
6. end.
7.  

[marcov]

Prints two times the same here. (fpc 3.0 on the win32 console)

possible reasons:
- settings relating to sourcecode encoding
- some lazarus feature that changes the default encoding.

[engkin]

The first one is written using fpc_write_text_shortstr, no codepage conversion is involved. You'll see the correct letter if your console output codepage has é for #130.

The second one is written using fpc_Write_Text_AnsiStr, a codepage conversion happens from DefaultSystemCodePage to TextRec(Output).CodePage:

Code: Pascal  [Select][+][-]

1.   WriteLn('DefaultSystemCodePage: ', DefaultSystemCodePage);
2.   WriteLn('TextRec(Output).CodePage: ', TextRec(Output).CodePage);

This conversion could corrupt the letter based on the two codepages.

[Roland57]

@engkin, marcov

Thank you for your answers.

Indeed, with {$codepage UTF8} the result is correct. (The source code encoding is UTF-8 without BOM.)

But I get a warning: Implicit string type conversion from "AnsiString" to "UnicodeString". It isn't really a problem (since the result is correct), but I wonder what I should write to avoid the warning.

Here is my full code:

Code: Pascal  [Select][+][-]

1. program touchdirectory;
2. {$codepage UTF8}
3.  
4. uses
5.   SysUtils, DateUtils, Process;
6.  
7. const
8.   TOUCH = 'C:\BCC101\bin\touch.exe';
9. // https://www.embarcadero.com/fr/free-tools/ccompiler
10.  
11. var
12.   year, month, day, hour, minute, second, millisecond: word;
13.   stamp, path: string;
14.  
15. begin
16.   if (ParamCount = 1) and DirectoryExists(ParamStr(1)) then
17.   begin
18.     path := ParamStr(1) + '\';
19.     WriteLn('Traitement du répertoire "' + path + '".');
20.   end else
21.   begin
22.     path := '';
23.     WriteLn('Traitement du répertoire courant.');
24.   end;
25.  
26.   DecodeDateTime(Now(), year, month, day, hour, minute, second, millisecond);
27.   stamp := Format('%0.2d%0.2d%0.2d%0.2d%0.2d', [month, day, hour, 0, year mod 100]);
28.  
29.   with TProcess.Create(nil) do
30.   begin
31.     Executable := TOUCH;
32.     Parameters.Add('-d' + stamp);
33.     Parameters.Add('-D');
34.     Parameters.Add('-s');
35.     Parameters.Add('-v');
36.     Parameters.Add(path + '*.*');
37.     Options := Options + [poWaitOnExit];
38.     Execute;
39.     Free;
40.   end;
41.  
42.   Write('Appuyez sur Entrée pour continuer... ');
43.   ReadLn;
44. end.
45.  

[Roland57]

The first one is written using fpc_write_text_shortstr, no codepage conversion is involved. You'll see the correct letter if your console output codepage has é for #130.

The second one is written using fpc_Write_Text_AnsiStr, a codepage conversion happens from DefaultSystemCodePage to TextRec(Output).CodePage:

Code: Pascal  [Select][+][-]

1.   WriteLn('DefaultSystemCodePage: ', DefaultSystemCodePage);
2.   WriteLn('TextRec(Output).CodePage: ', TextRec(Output).CodePage);

This conversion could corrupt the letter based on the two codepages.

Thank you for the explanations and for the code.

[engkin]

But I get a warning: Implicit string type conversion from "AnsiString" to "UnicodeString". It isn't really a problem (since the result is correct), but I wonder what I should write to avoid the warning.

Assuming you are using Lazarus, I know of two possibilities:

1-Hide the warning in this specific instance, using Lazarus IDE directive {%H-} at the location the warning is generated. In this case exactly to the left side of the variable path without leaving a space:

Code: Pascal  [Select][+][-]

1.     WriteLn('Traitement du répertoire "' + {%H-}path + '".');

2-Hide all instances by passing -vm4104 to the compiler in the project options.

You'll see both if you right-click on that warning.

[Roland57]

@engkin

I learn many things today! Thank you. 
 

[Tomas Hajny]

Note that the warning about implicit conversions may be avoided also by either using an explicit conversion (like: Ansistring ('répertoire')), or by not mixing UnicodeString (your constant) and ansistring (your variables). Both are probably better solutions than just hiding the warning.