Incompatible char and widechar in Delphi - delphi

Question

I have a strange problem.
I'm using Delphi 2007 and running it with the -r switch. On my computer everything works fine. When I transfer code to another computer I get an error:
Incompatible types char and widechar.
Maybe I should change some options.
Function that makes the problem:
function THcp.ConVertString(s: string): string;
Var i:integer;
lstr:string;
begin
lstr:=EmptyStr;
for i := 1 to Length(s) do
begin
case s[i] of
'Č': s[i]:='C';
'č': s[i]:='c';
'Ć': s[i]:='C';
'ć': s[i]:='c';
'Š': s[i]:='S';
'š': s[i]:='s';
'Đ': s[i]:='D';
'đ': s[i]:='d';
'Ž': s[i]:='Z';
'ž': s[i]:='z';
end;
lstr:=lstr+s[i];
end;
Result:=lstr;
end;

Answer 1

This is my hypothesis. On the machine on which the code compiles, the non-ASCII characters in the code are all valid ANSI characters for that machine's locale. But the other machine uses a different locale under which some of those characters are not included in the >= 128 portion of the codepage. And hence those characters are promoted to WideChar and so of course are not compatible with AnsiChar.

Answer 2

The reason for this could very much be the reason David suggests.
If you declare the function like this:
function THcp.ConVertString(s: AnisString): AnsiString;
Then that reason yet only applies for the character constants in your code, not for the input. By elimination of those constants by using the character order instead, like I once did in these routines, then I suppose this will compile.
function AsciiExtToBase(Index: Byte): Byte; overload;
const
Convert: array[128..255] of Byte = (
//128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146
// € ‚ ƒ „ … † ‡ ˆ ‰ Š ‹ Œ Ž ‘ ’
// E , f " ^ S < Z ' '
69,129, 44,102, 34,133,134,135, 94,137, 83, 60,140,141, 90,143,144, 41, 41,
//147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
// “ ” • – — ˜ ™ š › œ ž Ÿ ¡ ¢ £ ¤ ¥
// " " - ~ s > z Y !
34, 34,149, 45,151,126,153,115, 62,156,157,122, 89,160, 33,162,163,164,165,
//166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184
// ¦ § ¨ © ª « ¬ * ® ¯ ° ± ² ³ ´ µ ¶ · ¸
// | c a < - 2 3 '
124,167,168, 99, 97, 60,172, 45,174,175,176,177, 50, 51, 41,181,182,183,184,
//185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203
// ¹ º » ¼ ½ ¾ ¿ À Á Â Ã Ä Å Æ Ç È É Ê Ë
// 1 > ? A A A A A A A C E E E E
49,186, 62,188,189,190, 63, 65, 65, 65, 65, 65, 65, 65, 67, 69, 69, 69, 69,
//204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222
// Ì Í Î Ï Ð Ñ Ò Ó Ô Õ Ö × Ø Ù Ú Û Ü Ý Þ
// I I I I D N O O O O O x U U U U Y
73, 73, 73, 73, 68, 78, 79, 79, 79, 79, 79,120,216, 85, 85, 85, 85, 89,222,
//223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241
// ß à á â ã ä å æ ç è é ê ë ì í î ï ð ñ
// a a a a a a a c e e e e i i i i o n
223, 97, 97, 97, 97, 97, 97, 97, 99,101,101,101,101,105,105,105,105,111,110,
//242 243 244 245 246 247 248 249 250 251 252 253 254 255
// ò ó ô õ ö ÷ ø ù ú û ü ý þ ÿ
// o o o o o / u u u u y y
111,111,111,111,111, 47,248,117,117,117,117,121,254,121);
begin
if Index < 128 then
Result := Index
else
Result := Convert[Index];
end;
function AsciiExtToBase(AChar: AnsiChar): AnsiChar; overload;
begin
Result := Chr(AsciiExtToBase(Ord(AChar)));
end;
function AsciiExtToBase(const S: AnsiString): AnsiString; overload;
var
P: PByte;
I: Integer;
begin
Result := S;
P := #Result[1];
for I := 1 to Length(Result) do
begin
P^ := AsciiExtToBase(P^);
Inc(P);
end;
end;