Specifiers
本文参考cppreference Declarations的Specifiers章节。
typedef specifier
Function specifiers
function specifiers (inline, virtual, explicit), only allowed in function declarations
friend specifier
the friend specifier, allowed in class and function declarations.
constexpr consteval constinit specifier
上述三个specifier都是以const打头。
storage class specifier
storage class specifier (register, static, thread_local (since C++11), extern, mutable). Only one storage class specifier is allowed, except that thread_local may appear together with extern or static.
Type specifiers (type-specifier-seq)
此处略去。