Function maybe_pick_random_substring

crawl-ref/source/stringutil.cc:433–448

For each set of [phrase|term|word] contained in the string, replace the set with a random subphrase. NOTE: Doesn't work for nested patterns!

// For each set of [phrase|term|word] contained in the string, replace the set with a random subphrase.
// NOTE: Doesn't work for nested patterns!
string maybe_pick_random_substring(string s)
{
    string::size_type start = 0;
    while ((start = s.find("[", start)) != string::npos)
    {
        string::size_type end = s.find("]", start);
        if (end == string::npos)
            break;

        string substring = s.substr(start + 1, end - start - 1);
        vector<string> split = split_string("|", substring, false, true);
        int index = random2(split.size());
        s.replace(start, end + 1 - start, split[index]);
    }
    return s;
}

int count_occurrences(const string &text, const string &s)
{