string literals as template parameters, sort of

It is very long standing problem of C++ that you cannot use string literals as template parameters.

I acknowledge that macros are bad, however..

C++ lambdas have a special property of generating anonymous unique types.

Therefore a scope in which to create additional types.

This seems to be quite useful. It seems like producing types (or functions) within lambdas within macros provides template-like powers, and not in the bad old way that macros on their own do.

I'm not sure where all this will go, but here is a start:

#include <stdio.h>

#include <string>

#define STRING_TEMPLATE_FUNCTION(str) \

    []() { struct Type { static const char* Function() { return str; } }; return Type::Function; }()

#define STRING_TEMPLATE_CLASS(str) \

    [=]() { struct Type : std::string { using std::string::operator=; Type() : std::string(str) { } }; return []{ return Type();}(); }()

int main()

{

    auto foo = STRING_TEMPLATE_FUNCTION("foo");

    auto bar = STRING_TEMPLATE_CLASS("bar");

    auto bar2 = STRING_TEMPLATE_CLASS("bar2");

    printf("%s\n", foo());

    printf("%s\n", bar.c_str());

    printf("%s\n", bar2.c_str());

    bar = bar2;

    printf("%s\n", bar.c_str());

}