Note that the form shown here wasn't accepted into the standard, as noted below.
Compile time string processing is guessed to become possible through user-defined literals proposed in N2765.
As i already mentioned, i don't know of any compiler that currently implements it and without compiler support there can be only guess work.
In §2.13.7.3 and 4 of the draft we have the following:
Otherwise (S contains a literal operator template), L is treated as a call of the form
operator "" X<'c1', 'c2', ... , 'ck'>() where n is the source character sequence c1c2...ck. [Note: The sequence c1c2...ck can only contain characters from the basic source character set. —end note]
Combine that with constexpr and we should have compile time string processing.
update: i overlooked that i was reading the wrong paragraph, this form is allowed for user-defined-integer-literals and -floating-literals, but apparently not for -string-literals (§2.13.7.5).
This part of the proposal seems to have not been accepted.
That being said, with my limited glimpse at C++0x, it might look something like this (i most likely got something wrong):
template<char c, char... str> struct hash { static const unsigned result = c + hash<str...>::result; }; template<char c> struct hash { static const unsigned result = c; }; template<char... str> constexpr unsigned operator "" _hash() { return hash<str>::result; } // update: probably wrong, because the above // form is not allowed for string-literals: const unsigned h = "abcd"_hash; If Jerrys approachJerrys approach works, then the following should work however:
constexpr unsigned operator "" _hash(const char* s, size_t) { return const_hash(s); } 
