avoiding the first newline in a C++11 raw string literal?

Question

The raw string literals in C++11 are very nice, except that the obvious way to format them leads to a redundant newline \n as the first character.

Consider this example:

    some_code();     std::string text = R"( This is the first line. This is the second line. This is the third line. )";     more_code(); 

The obvious workaround seems so ugly:

    some_code();     std::string text = R"(This is the first line. This is the second line. This is the third line. )";     more_code(); 

Has anyone found an elegant solution to this?

Answer 1

You can get a pointer to the 2nd character - skipping the leading newline - by adding 1 to the const char* to which the string literal is automatically converted:

    some_code();     std::string text = 1 + R"( This is the first line. This is the second line. This is the third line. )";     more_code(); 

---

IMHO, the above is flawed in breaking with the indentation of the surrounding code. Some languages provide a built-in or library function that does something like:

• removes an empty leading line, and
• looks at the indentation of the second line and removes the same amount of indentation from all further lines

That allows usage like:

some_code(); std::string text = unindent(R"(     This is the first line.     This is the second line.     This is the third line.     )"); more_code(); 

Writing such a function is relatively simple...

std::string unindent(const char* p) {     std::string result;     if (*p == '\n') ++p;     const char* p_leading = p;     while (std::isspace(*p) && *p != '\n')         ++p;     size_t leading_len = p - p_leading;     while (*p)     {         result += *p;         if (*p++ == '\n')         {             for (size_t i = 0; i < leading_len; ++i)                 if (p[i] != p_leading[i])                     goto dont_skip_leading;             p += leading_len;         }       dont_skip_leading: ;     }     return result; } 

(The slightly weird p_leading[i] approach is intended to make life for people who use tabs and spaces no harder than they make it for themselves ;-P, as long as the lines start with the same sequence.)

Answer 2

This is probably not what you want, but just in case, you should be aware of automatic string literal concatenation:

    std::string text = "This is the first line.\n" "This is the second line.\n" "This is the third line.\n";