Extended ASCII use - 2

[engkin]

Code: Pascal  [Select][+][-]

1.       c:=char(i);   // ! This is invalid in utf8 and leads to runtime error 101
2.  

What would be the correct way considering:

Code: Pascal  [Select][+][-]

1. {$mode objfpc}{$H+}
2. {$Codepage cp850}
3.  
4. var
5. ..
6.   i:byte;
7.   c:char;

[tetrastes]

In an ideal world it should return 4, imho. 

By the way, at linux

Code: C  [Select][+][-]

1. sizeof(wchar_t)

returns 4. 

[Thaddy]

Yes.

[tetrastes]

@engkin
To imitate CP850 at UTF8 console without errors:

Code: Pascal  [Select][+][-]

1. program project1;
2.  
3. {$mode objfpc}{$H+}
4. {$Codepage cp850}
5.  
6. {$IFDEF UNIX}
7. uses cwstring;    // We need properly working UnicodeManager, of course
8. {$ENDIF}
9.  
10. type
11.   CP850String = type AnsiString(850);
12.  
13. var
14.   s:array[0..3] of String;
15.   ss:string;
16.   i:byte;
17.   c:char;
18. begin
19.   WriteLn('DefaultSystemCodePage: ',DefaultSystemCodePage);
20.   WriteLn('TextRec(Output).CodePage: ',TextRec(Output).CodePage);
21.   ss:='ÄÇýÝ';
22.   WriteLn(ss);
23.  
24.   //CP850: #$80..#$FF
25.   s[0]:='ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø׃';
26.   s[1]:='áíóúñѪº¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐';
27.   s[2]:='└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ðÐÊËÈıÍÎÏ┘┌█▄¦Ì▀';
28.   s[3]:='ÓßÔÒõÕµþÞÚÛÙýݯ´­±‗¾¶§÷¸°¨·¹³²■';
29.   for i:=$80 to $FF do
30.   begin
31.     if (i mod 32)=0 then
32.     begin
33.       WriteLn();
34.       WriteLn();
35.       WriteLn(s[i div 32 - 4]);
36.     end;
37.     if i in [$07,$08,$09,$0A,$0D] then
38.       c:=' '
39.     else
40.       c:=char(i);
41.     Write(CP850String(c));    // SIC!
42.   end;
43. end.
44.  

[SymbolicFrank]

In an ideal world it should return 4, imho. 

Totally agree. Go Linux!

[engkin]

@tetrastes,

If chcp gave 850, what's the difference between:

Code: Pascal  [Select][+][-]

1.     Write(c);

and

Code: Pascal  [Select][+][-]

1.     Write(CP850String(c));

[tetrastes]

Casting char to string? The output is the same.
It's funny that at windows there is difference between

Code: Pascal  [Select][+][-]

1. write(c)

which outputs in console CP, and

Code: Pascal  [Select][+][-]

1. write(string(c))

which outputs in default system CP.
And you may change them independently. 

[engkin]

Casting char to string? The output is the same.
It's funny that at windows there is difference between

Code: Pascal  [Select][+][-]

1. write(c)

which outputs in console CP, and

Right, and that is what raymond wants.

[tetrastes]

But he wants it at linux with UTF8, where write(c) works only for c<128.

[engkin]

But he wants it at linux with UTF8, where write(c) works only for c<128.

In this case you are right, I missed that part. Thanks for correcting me.

[Thaddy]

Anybody knows why UnicodeChar differs from wchar_t ? (or similar in any other unicode supporting language!)
Currently it is just UCS2 size. It really should be size 4.
So OK on Delphi it is also size 2, I guess.
I suspect that a size 4 greatly simplifies handling codepoints.

[tetrastes]

Not only on Delphi, but windows itself.

Code: C  [Select][+][-]

1. sizeof(wchar_t)

is 2 at windows, 32 or 64 bit, gcc or cl.
So fpc loves windows. 

[PascalDragon]

Anybody knows why UnicodeChar differs from wchar_t ? (or similar in any other unicode supporting language!)
Currently it is just UCS2 size. It really should be size 4.
So OK on Delphi it is also size 2, I guess.
I suspect that a size 4 greatly simplifies handling codepoints.

Because Delphi defines UnicodeChar to be used with UTF-16 which has 2 Byte codepoints and Delphi in turn uses UTF-16, because Windows uses UTF-16. For UTF-32 there is UCS4Char (though this is not a true, builtin character type, but simply an alias to LongWord).

Not only on Delphi, but windows itself.

Code: C  [Select][+][-]

1. sizeof(wchar_t)

is 2 at windows, 32 or 64 bit, gcc or cl.
So fpc loves windows. 

No, for FPC Delphi-compatibility is the main driver and thus UnicodeChar is declared the same as it is in Delphi which - as written above - uses UTF-16 (and thus 2 Byte codepoints), because Windows uses UTF-16.

[tetrastes]

FPC follows Delphi, Delphi follows Windows... The leading sheep is Windows, anyway. 

[PascalDragon]

Even if Delphi or FPC would use a 4 Byte UnicodeChar there'd still be a need for a 2 Byte character to handle UTF-16. It's after all a reason why C++ introduced distinct char16_t and char32_t types in C++11 (see here).