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Inside a Macro, I can use the stringizing operator #:
#define STRINGIZE(name) #name
cout << STRINGIZE(SomeClass) << endl; // Prints "SomeClass"
Is it possible to do the opposite, unstringize inside a Macro? How?
For example:
#define RUN_FUNCTION(name) UNSTRINGIZE(name)();
void myFunction {
cout << "Hello!" << endl;
}
RUN_FUNCTION("myFunction") // Prints "Hello!"
If not, is there a reason why?
220
Spaces are produced, inside a macro as elsewhere, by space or tab characters, or by end-of-line characters.
The number-sign or "stringizing" operator (#) converts macro parameters to string literals without expanding the parameter definition. It's used only with macros that take arguments.
We can create two or more than two strings in macro, then simply write them one after another to convert them into a concatenated string. The syntax is like below: #define STR1 "str1" #define STR2 " str2" #define STR3 STR1 STR2 //it will concatenate str1 and str2.
The double-number-sign or token-pasting operator (##), which is sometimes called the merging or combining operator, is used in both object-like and function-like macros. It permits separate tokens to be joined into a single token, and therefore, can't be the first or last token in the macro definition.
No, it's not possible. The C++ preprocessor cannot break up tokens into smaller tokens in any way.
What exactly is it that you're trying to do? There's almost certainly a better way of doing it.
120
[Promoted from comment]
Preprocessing takes place before compilation, which is before runtime. You'd need reflection to do that without defining your own rules, which requires some form of metadata, and C++ doesn't have it.
I can't find where, but I recently saw somewhere (perhaps here, but according to Wikipedia, it's been postponed) that reflection could be coming to C++ sometime in the future, so there might be a prospect there.
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