bf_templates.cpp

#include <iostream>
#include <string>
#include <sstream>
#include <fstream>

std::stringstream prog;

constexpr unsigned c_strlen( char const* str, unsigned count = 0 )
{
    return ('\0' == str[0]) ? count : c_strlen(str+1, count+1);
}

template < char t_c, char... tt_c >
struct rec_eval
{
    static void eval()
    {
        rec_eval<t_c>::eval();
        rec_eval < tt_c... > :: eval ();
    }
};
template < char t_c >
struct rec_eval < t_c >
{
	static void eval() {
		switch(t_c) {
			case '+':
				prog<<"++t[i];";
				break;
			case '-':
				prog<<"--t[i];";
				break;
			case '>':
				prog<<"++i;";
				break;
			case '<':
				prog<<"--i;";
				break;
			case '[':
				prog<<"while(t[i]){";
				break;
			case ']':
				prog<<"}";
				break;
			case '.':
				prog<<"putc(t[i],stdout);";
				break;
			case ',':
				prog<<"t[i]=getchar();";
				break;
		}
	}
};

template < char... tt_c >
struct exploded_string
{
    static void eval()
    {
        rec_eval < tt_c... > :: eval();
    }
};
template < typename T_StrProvider, unsigned t_len, char... tt_c >
struct explode_impl
{
    using result =
        typename explode_impl < T_StrProvider, t_len-1,
                                T_StrProvider::str()[t_len-1],
                                tt_c... > :: result;
};

template < typename T_StrProvider, char... tt_c >
struct explode_impl < T_StrProvider, 0, tt_c... >
{
	 using result = exploded_string < tt_c... >;
};

template < typename T_StrProvider >
using explode =
    typename explode_impl < T_StrProvider,
                            c_strlen(T_StrProvider::str()) > :: result;


int main(int argc, char** argv)
{
	if(argc < 2) return 1;
	prog << "#include <stdio.h>\n#include <stdlib.h>\nint main(){unsigned char* t=calloc(";
	prog << (1 << sizeof(unsigned short));
	prog << ",sizeof(unsigned short));unsigned short i=0;";
	
    struct my_str_provider
    {
        constexpr static char const* str() { return "++++[>+++++<-]>+++[[>+>+<<-]>++++++[<+>-]+++++++++[<++++++++++>-]>[<+>-]<-]+++>+++++++++[<+++++++++>-]>++++++[<++++++++>-]<--[>+>+<<-]>>[<<+>>-]<-->>++++[<++++++++>-]++++++++++>+++++++++[>+++++++++++<-]>[[>+>+>+<<<-]>[<+>-]>>[[>+>+<<-]>>[<<+>>-]<[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<<<+>---------->->[-]]]]]]]]]]]<]<<[>>++++++++++++[<++++<++++>>-]<<[.[-]>]<<]>[<++++++[>++++++++<-]>.[-]]<<<<<.<<<<<.[<]>>>>>>>>>.<<<<<..>>>>>>>>.>>>>>>>.[>]>[>+>+<<-]>[<+>-]>[-[[-]+++++++++[<+++++++++++++>-]<--.[-]>]]<<<<<.[<]>>>>>>>>>.>>>>>>>>>.[>]<<.<<<<<.<<<..[<]>>>>>>.[>]<<.[<]>>>>>>>>>.>.[>]<<.[<]>>>>.>>>>>>>>>>>>.>>>.[>]<<.[<]>.[>]<<<<<<.<<<<<<<<<<<..[>]<<<.>.[>]>[>+>+>+<<<-]>[<+>-]>>[[>+>+<<-]>>[<<+>>-]<[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<<<+>---------->->[-]]]]]]]]]]]<]<<[>>++++++++++++[<++++<++++>>-]<<[.[-]>]<<]>[<++++++[>++++++++<-]>.[-]]<<<<<.<<<<<.[<]>>>>>>>>>.<<<<<..>>>>>>>>.>>>>>>>.[>]>[>+>+<<-]>[<+>-]>[-[[-]+++++++++[<+++++++++++++>-]<--.[-]>]]<<<<<.[<]>>>>>>>>>.>>>>>>>>>.[>]<<.<<<<<.<<<..[<]>>>>>>.[>]<<<<.>>>.<<<<.<.<<<<<<<<<<.>>>>>>.[>]<<.[<]>>>>>>>>>.>.>>>>>>>>>.[>]<<.<<<<<<<.[<]>>>>>>>>>.[<]>.>>>>>>>>>.[>]<<.<<<<.<<<<<<<<<<<<<.[>]<<<<<<<<<.[>]<<.[<]>>>>>>>>.[>]<<<<<<.[<]>>>>>..[>]<<.<<<<<<<<<<<<.[<]>>>>.[>]<<.<<<<.[<]>>>>>>.>>>.<<<<<<.>>>>>>>.>>>>>>>>>>.[>]<<<.>.>>>-[>+>+>+<<<-]>[<+>-]>>[[>+>+<<-]>>[<<+>>-]<[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<->-[<<<+>---------->->[-]]]]]]]]]]]<]<<[>>++++++++++++[<++++<++++>>-]<<[.[-]>]<<]>[<++++++[>++++++++<-]>.[-]]<<[>+>+<<-]>[<+>-]+>[<->[-]]<[-<<<[<]>>>>>>>>>>.<.[>]<<.[<]>>>>>>>>>>>.<<.<<<.[>]<<<<<<<<<<.[>]>>]<<<<.<<<<<.[<]>>>>>>>>>.<<<<<..>>>>>>>>.>>>>>>>.[>]>[>+>+<<-]>[<+>-]+>[<->-[<+>[-]]]<[++++++++[>+++++++++++++<-]>--.[-]<]<<<<.[<]>>>>>>>>>.>>>>>>>>>.[>]<<.<<<<<.<<<..[<]>>>>>>.[>]<<.[<]>>>>>>>>>.>.[>]<<.[<]>>>>.>>>>>>>>>>>>.>>>.[>]<<.[<]>.[>]<<<<<<.<<<<<<<<<<<..[>]<<<<.>>>..>>]"; }
    };

    auto my_str = explode < my_str_provider >{};
    my_str.eval();
	
	prog << "}";
	
	std::ofstream ofs(argv[1]);
	if(!ofs) return 2;
	ofs << prog.str() << std::endl;
	ofs.close();
	
	return 0;
}