[Lazarus] Unable to display symbols

[Giuliano Colla]

Il 08/03/2014 14:05, Mattias Gaertner ha scritto:
> On Sat, 08 Mar 2014 13:52:12 +0100
> Giuliano Colla <giuliano.colla at fastwebnet.it> wrote:
> [snip]
>> What I'm doing wrong?
> The solution lies in your own mail. Your mail is UTF-8 and so are the
> above characters. Just copy the above characters from your mail to the
> IDE:
>
> aText := 'SomeString¥';
>
> Note: Keep in mind that "char" is a single byte, but ¥ in UTF-8 is
> multiple bytes.
>

I was aware of that. My problem is that the char I must add to the Utf8 
string is calculated run time, and is in the range Unicode $A0-$BF.

I had assumed (wrongly) that the compiler was smart enough to convert a 
type "char" to UTF8, when concatenating it to an UTf8 string. Instead it 
turns out that the character is appended as it is, which leads to an 
invalid UTF8 character (above 127), which displays as a crossed box.
IMHO that's an FPC bug.

When I realized that, I then tried to explicitly convert the Unicode 
char to UTF8, but again I failed, this time because of the default 
behavior which is to map char <-> Unicode only in the range 0-127. 
Anything above 127 becomes a question mark.
Therefore my symbol displays as a question mark.
IMHO that's a silly FPC limitation.

The only way out I found was to build a table of UTf8 strings in the 
correct range (corresponding to the Unicode symbols from $A0 to $BF),  
and use my calculated value as an index to that table.

Rather cumbersome and inelegant, if you think that in the unit ustrings 
there's an UnicodeToUtf8 routine, which performs exactly the required 
conversion, but which can't be used because of the above silly limitation.

Giuliano