Pass a string Recursively without Recreation

Question

I answered a question here: https://stackoverflow.com/a/28862668/2642059 Where I needed to use recurrence to step through a string. I wanted to use a cons

Answer 1

string_view from the library fundamentals TS might be one idea, support is available in GCC.

The interface is virtually identical to string

#include 
using std::experimental::string_view;

string_view foo(const string_view& bar){
    auto start = bar.find('(') + 1;

    return start == string_view::npos + 1 ? bar : foo(bar.substr(start, bar.find_last_of(')') - start));
}

The last line could also be

return start ? foo(bar.substr(start, bar.find_last_of(')') - start)) : bar;

Although they're both pretty cryptic.