Escaping blocks of foreign code in C++

Question

If your compiler can be made to accept C++11 standard, you could use raw string literals like eg:

  std::cout << R"*(<!DOCTYPE html>
       <html>
       <head>
       <title>Title with a backslash \ here 
     and double " quote</title>)*";

Hence with raw string literals there is no forbidden sequence of characters in those raw string literals. Any sequence of characters could appear in them (but you can define the ending sequence of the raw string)

And you could use #{ and }# like I do in MELT macro-strings; MELT is Lisp-like domain specific language to extend GCC, and you can embed code in it with e.g.

(code_chunk hellocount_chk
            #{ /* $HELLOCOUNT_CHK chunk */ 
                 static int $HELLOCOUNT_CHK#_counter; 
                 $HELLOCOUNT_CHK#_counter++;
               $HELLOCOUNT_CHK#_lab:
                 printf ("Hello World, counted %d\n", 
                         $HELLOCOUNT_CHK#_counter);
                 if (random() % 4 == 0) goto $HELLOCOUNT_CHK#_lab;
            }#)

The #{ and }# are enclosing macro-strings (these character sequences are unlikely to appear in C or C++ code, except in string literals and comments), with the $ starting symbols in such macro-strings (up to a non-letter or # character).

^{Using #{ and }# is not fool-proof (e.g. because of raw string literals) but good enough: a cooperative user could manage to avoid them.}