itoa.cpp

#include <fcitx-utils/metastring.h>
#include <iostream>

template<int b>
class ItoA2 {
public:
    using cur = typename ItoA2<b % 10>::type;
    using remain = typename ItoA2<b / 10>::type;
    using type = typename fcitx::ConcatMetaString<remain, cur>::type;
};

#define ITOA2_DEF(N) template<> class ItoA2<N> { public: using type = fcitx::MetaString<N + '0'>; };
ITOA2_DEF(0);
ITOA2_DEF(1);
ITOA2_DEF(2);
ITOA2_DEF(3);
ITOA2_DEF(4);
ITOA2_DEF(5);
ITOA2_DEF(6);
ITOA2_DEF(7);
ITOA2_DEF(8);
ITOA2_DEF(9);

int main() {
    ItoA2<1234215>::type b;
    std::cout << b.data() << std::endl;
    return 0;
}