C++ Compile-Time string manipulation

Question

I looked at boost's mpl::string, but there doesn't seem to be an easy way of converting string literals to the single-quotation-integer-based format of mpl::string. What I am trying to do is to generate at compile time an XML realization of some simple data structures using compile time strings. I am striving for having macros generate the structures themselves and insert a constant "meta" field inside them, containing said XML string.

score 3 · Answer 1 · answered Sep 15 '10 at 21:14

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The short answer is no, there is no easy way. At least not using C++ alone, and at compile time. You can use scripts or some other code generator to produce mpl::strings with the correct literals. C++0x will bring user defined literals [1], that allow an easy manipulation of literals, character by character, for example, using variadic templates.

http://en.wikipedia.org/wiki/C%2B%2B0x#User-defined_literals

answered Sep 15 '10 at 21:14

Diego Sevilla

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Is there any guarantee that user defined literals are processed at compile time? I always assumed we are at the mercy of the optimizer for that. – peterchen Jan 07 '11 at 10:44
The question is that they are at least passed to the program in an easy writable and maintainable manner, that is, you don't have to write `'a','b','c',...`. – Diego Sevilla Jan 10 '11 at 17:13

score 0 · Answer 2 · answered Dec 05 '12 at 21:31

Here is an article regarding the subject: http://akrzemi1.wordpress.com/2011/05/11/parsing-strings-at-compile-time-part-i/. The author implements a simple RPN arithmetic calculator that works during compile-time using user string literals and constexpr. I won't attempt to provide any more summary of the article here.

C++ Compile-Time string manipulation

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