pcre_replace_callback

pcre_replace_callback() - string replace uses a callback to get the replace string

string pcre_replace_callback(string input, string pattern, string|function, mixed *args...);

returns a string where all captured groups have been replaced by the return
value of function pointer fun or function fun in object ob. (called with the
matched string and match number, starting with 0)

pcre_assoc(3), pcre_cache(3), pcre_extract(3), pcre_replace(3)