运营商... [英] Operator...
问题描述
之前可能已经提出过很多问题，但我只是想念它。
为什么没有像这样的东西操作员...（）
imho它可以让我们平滑c +
+的一个更尖锐的角落。
你可以做这样的事情：
类字符串
{
public：
const char * operator ...（）const
{
返回c_str（）;
}
};
void foo（const char * format，...）
{
//通常的vaarg东西
}
void bar（）
{
string s =" test";
foo（这是一个测试％s，s）;
}
只是一个快速思考，
M.
this has probably been asked/suggested many timtes before, but i just
thought of it.
why is there no such thing as something like operator...()
imho it would allow us to smooth off one of the sharper corners of c+
+.
you could maybe do something like this:
class string
{
public:
const char *operator...() const
{
return c_str();
}
};
void foo(const char *format, ...)
{
//the usual vaarg stuff
}
void bar()
{
string s = "test";
foo("this is a test %s", s);
}
just a quick thought,
M.
推荐答案
ma *********** @ hotmail.com 写道：
这可能是之前被问过/建议很多，但我只是想想它。$ / b
为什么没有像运算符这样的东西......（）
imho它可以让我们平滑c +
+的一个更尖锐的角落。
你可以做这样的事情：
类字符串
{
公开：
const char * operator ...（）const
{
返回c_str（）;
}
};
void foo（const char * format，...）
{
//通常的vaarg东西
}
void bar（）
{
string s =" test" ;
foo（这是测试％s，s）;
}
只是快速思考，
this has probably been asked/suggested many timtes before, but i just
thought of it.
why is there no such thing as something like operator...()
imho it would allow us to smooth off one of the sharper corners of c+
+.
you could maybe do something like this:
class string
{
public:
const char *operator...() const
{
return c_str();
}
};
void foo(const char *format, ...)
{
//the usual vaarg stuff
}
void bar()
{
string s = "test";
foo("this is a test %s", s);
}
just a quick thought,
嗯，乍一看它看起来还不错，但后来我想，所以为什么不能给你b
只需要
foo（这是一个测试％s ;，s.c_str（））;
？如果不改变
语言，它将完成完全相同的事情。你是否认为你可以通过使用static_cast<或已经存在
的成员函数来解决这个问题？
？
一般来说，你推广的是最低级别的转换运算符
，当没有其他标准或用户定义的转换时可以使用
适合，我猜。由于我不会使用那么多的转换，所以我不能立即看到其他地方（除了实际的''...''）
会很有用。
V
-
请在通过电子邮件回复时删除资金'A'
我没有回复最热门的回复，请不要问
Well, on the first glance it looked OK, but then I thought, so why can''t
you just do
foo("this is a test %s", s.c_str());
? It would accomplish the exactly same thing without changing the
language. Do you think you could give an example that couldn''t be
countered by a use of a static_cast<or a member function that already
exists?
Generally speaking, you''re promoting the lowest rank conversion operator
which can be used when no other standard or user-defined conversion is
suitable, I am guessing. Since I don''t use conversions that much I
can''t really immediately see where else (aside from the actual ''...'') it
would be useful.
V
--
Please remove capital ''A''s when replying by e-mail
I do not respond to top-posted replies, please don''t ask
是的，标准的事情是必须打电话给s。 c_str（）。
标准板故意没有将操作符char *放入
字符串中，原因是你无法使std :: string类行为
完全像一个pod类型，就像其他语言一样，因为变量
参数。
i意味着这只是作为一个类beign的可能转换通过
进入变量参数参数列表。它是其中一个让人们接受的东西，让其他程序员想知道为什么c ++不是什么时候
更有帮助。
只是觉得它可能是一个方便的小补充。
M.
yeah the standard thing is to have to call s.c_str().
the standards board purposefully didnt put an operator char* into
string for the reason that you cant make the std::string class act
entirely like a pod type like in other languages because of variable
arguments.
i meant this only as a possible conversion for a class beign passed
into a variable argument parameter list. its one of those things that
catches people out, and makes other programmers wonder why c++ isnt
more helpfull some times.
just thought it could be a handy little addition.
M.
ma *********** @ hotmail.com 写道：
之前可能有人问过/建议很多，但我只是想念它。
为什么没有这样的东西像操作员...（）
imho它可以让我们平滑c +
+的一个更尖锐的角落。
this has probably been asked/suggested many timtes before, but i just
thought of it.
why is there no such thing as something like operator...()
imho it would allow us to smooth off one of the sharper corners of c+
+.
下一个C ++标准将引入可变参数模板，这将允许写入类型安全的函数，这些函数采用可变数量的
参数。我相信这将允许你做你所指的
到这里。
The next C++ standard will introduce variadic templates, which will
allow writing type-safe functions which take a variable amount of
parameters. I believe that will allow you to do what you are referring
to here.
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