I'm designing a public API in C++ and believe I'd like to retain C++ property-function style conventions that look like int& Value()
, and const int& Value() const
as opposed to get/set prefixes which return/assign by value because I feel the usage patterns are more concise and equally readable, while blending into existing C++ code very easily.
I need to allow the programmer to supply his own metadata. I've chosen to do so by exposing a void*
property function. The problem is of course that having signatures like:
class foo {
int& Value();
const int& Value() const;
void* Metadata()
void* const Metadata() const
};
...doesn't work because the following won't compile:
void* ptr = ...;
foo.Metadata() = ptr;
Because of this, I would have to use something like the following to make it work:
class foo {
int& Value();
const int& Value() const;
void* GetMetadata();
开发者_运维百科 void SetMetadata(void* const data);
};
But that would render the styles inconsistent, so for now I've opted to stick with get/set prefixes throughout the entire API because of that, eg:
class foo {
int GetValue() const;
void SetValue(int value);
void* GetMetadata() const;
void SetMetadata(void* const data);
};
Of course, that doesn't fit the language convention I'd like to use. Is there an alternative approach to this whole thing? If so, what is it? Am I stuck with get/set prefixes?
Note: I can't replace void*
with templates for user meta-data as the API should be as stable as possible.
Also, I have already supplied a string get/set pair typed unsigned char*
for user strings.
UPDATE:
After some careful (re)consideration I've opted to stick with get/set prefixes, I also won't use references for void*
- if void*
gives off a smell, void*&
is pretty much a public landfill. As such, I've essentially opted for something similar to this:
typedef void* Any;
class foo {
...
Any GetObject() const;
void SetObject(Any);
...
};
Thanks for your input. :)
Not that I'm sure this is the best design but, sticking to the question: If, for an attribute of type "int", you write:
int& Value(); //Used as setter
int Value()const; //Used as getter
do the same for an attribute of type "void*":
void*& Meta(); //Used as setter
void* Meta()const; //Used as getter
You could have your Metadata
functions return references to pointers:
class foo {
int& Value();
const int& Value() const;
void*& Metadata()
const void* const & Metadata() const
};
Another alternative is to use overloading:
class foo{
int Value() const;
void Value(int);
void* Metadata() const;
void Metatdata(void*);
};
If you go this route, you could also make the setters return the old value for convenience.
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