In C++ why isn't "assert" a keyword?

Question

Now "static_assert" is a keyword in C++0x I thought it would be logical to replace the C "assert" macro with an "assert" keyword too.

Answer 1

static_assert is interpreted at compile time so it has to be a keyword so the compiler can process it.

assert doesn't need to be a keyword, and it doesn't make much sense to make it one, since there are many ways a program might want to respond to assertion success or failure. Therefore, it makes more sense to implement it in a library, and it is typically implemented as a macro.