+/// substitutes all instances of \a oldstr with \a newstr
+docstring const subst(docstring const & a,
+ docstring const & oldstr, docstring const & newstr);
+
+/** Trims characters off the end and beginning of a string.
+ \code
+ trim("ccabccc", "c") == "ab".
+ \endcode
+*/
+docstring const trim(docstring const & a, char const * p = " ");
+