delphi - 如何在非 unicode Delphi 版本中构造带有变音符号的 WideString？

Question

我正在尝试构建一个(测试)WideString:

á (U+00E1 Small Letter Latin A with acute)

但是使用它的分解形式:

LATIN SMALL LETTER A (U+0061) COMBINING ACUTE ACCENT (U+0301)

所以我有代码片段:

var
    test: WideString;
begin
   test := #$0061#$0301;
   MessageBoxW(0, PWideChar(test), 'Character with diacratic', MB_ICONINFORMATION or MB_OK);
end;

但它似乎不起作用:

这可能是 MessageBox 中的错误，但我要继续说，该错误更有可能出现在我的代码中。

我尝试过的其他一些变体:

test := WideString(#$0061#$0301);


const
    SmallLetterLatinAWithAcuteDecomposed: WideString = #$0061#$0301;
test := SmallLetterLatinAWithAcuteDecomposed


test := #$0061+#$0301;  (Doesn't compile; incompatible types)


test := WideString(#$0061)+WideString(#$0301);  (Doesn't compile; crashes compiler)


test := 'a'+WideString(#$0301);  (Doesn't compile; crashes compiler)


//Arnauld's thought:
test := #$0301#$0061;

奖金闲聊

• Handling a Unicode String in Delphi Versions <= 2007

Answer 1

最佳答案:

const
    n: WideString = '';  //n=Nothing

s := n+#$0061+#$0301;

这修复了我下面遇到的所有情况，否则会失败。

<小时/>

唯一有效的变体是将其声明为常量:

AccentAcute: WideString = #$0301;
AccentAcute: WideString = WideChar($0301);
AccentAcute: WideString = WideChar(#$0301);
AccentAcute: WideString = WideString(#$0301);

用法示例:

s := 'Pasta'+AccentAcute;

基于常量的语法不起作用

• AccentAcute:WideString = $0301;
  不兼容的类型
• AccentAcute:WideString = #0301;
  给出
• AccentAcute:WideString = WideString($0301);
  类型转换无效
• AccentAcute:WideString = WideString(#$0301);
  类型转换无效
• AccentAcute: WideChar = WideChar(#0301);
给出Pastai
• AccentAcute: WideChar = WideChar($0301);
提供意大利面

其他失败的语法

• '意大利面'+WideChar($0301)
  提供意大利面
• '意大利面'+#$0301
  提供意大利面
• WideString('意大利面')+#$0301
  给出

<小时/>

我发现的所有基于常量的语法的总结:

AccentAcute: WideString =            #$0301;   //works
AccentAcute: WideString =   WideChar(#$0301);  //works
AccentAcute: WideString = WideString(#$0301);  //works
AccentAcute: WideString =             $0301;   //incompatble types
AccentAcute: WideString =    WideChar($0301);  //works
AccentAcute: WideString =  WideString($0301);  //invalid typecast

AccentAcute: WideChar =            #$0301;     //fails, gives Pasta´
AccentAcute: WideChar =   WideChar(#$0301);    //fails, gives Pasta´
AccentAcute: WideChar = WideString(#$0301);    //incompatible types
AccentAcute: WideChar =             $0301;     //incompatible types
AccentAcute: WideChar =    WideChar($0301);    //fails, gives Pasta´
AccentAcute: WideChar =  WideString($0301);    //invalid typecast

只要您仅附加到变量，重新排列 WideChar 就可以了

//Works
t := '0123401234012340123';
t := t+WideChar(#$D840);
t := t+WideChar(#$DC00);

//fails
t := '0123401234012340123'+WideChar(#$D840);
t := t+WideChar(#$DC00);

//fails
t := '0123401234012340123'+WideChar(#$D840)+WideChar(#$DC00);

//works
t := '0123401234012340123';
t := t+WideChar(#$D840)+WideChar(#$DC00);

//works
t := '';
t := t+WideChar(#$D840)+WideChar(#$DC00);

//fails; gives junk
t := ''+WideChar(#$D840)+WideChar(#$DC00);

//crashes compiler
t := WideString('')+WideChar(#$D840)+WideChar(#$DC00);

//doesn't compile
t := WideChar(#$D840)+WideChar(#$DC00);

绝对是针对编译器的废话；未经过充分测试的案例。是的，我知道大卫，我们应该升级。