Hi,
From: Fernando Pelliccioni
A little code improvement
template<typename ArrayType, size_t N> constexpr ArrayType nth( const ArrayType (&s)[N], int n ) { return n>= N ? 0 : s[n]; } Hmmm, now that I think of it:
int S[] = {1, 1, 2, 3, 5, 8};
some_template<nth<size_of(S)>(S, 3)>
is pretty nice to have in TMP too.
Thanks, Luke
I made an implementation of it part of the compile-time parsing library (metaparse) on github. Its purpose is to simplify the definition of boost::mpl::string values the following way: instead of boost::mpl::string<'hell','o wo','rld'> you can write _S("hello world") It has an "nth" (I called it array_at there) constexpr function and a metafunction building the mpl::string. Using a helper metafunction it converts string literals of any length (up to MPLLIBS_METAPARSE_STRING_MAX_LENGTH) to boost::mpl::string. It uses a helper metafunction to avoid appending 0 characters at the end when the string literal is shorter than the max length. Implementation: https://github.com/sabel83/mpllibs/blob/master/mpllibs/metaparse/string.hpp. It contains Fernando's improvement to the code as well. Regards, Ábel