Like C++ classes, each Mythryl package has its own internal namespace in which its elements live. Each element may be a type, value, constructor, subpackage, and thus may have as name an operator, lower-case, mixed-case or upper-case identifier.
Much as in C++, elements of other packages may be referenced using compound identifiers of the form package::element:
posix::File_Descriptor # Reference a type in package "posix".
posix::(|) # Reference an operator in package "posix".
posix::fd_to_int # Reference a function in package "posix".
posix::stdin # Reference a value in package "posix".
posix::MAY_READ # Reference a constructor in package "posix".
posix::posix_file # Reference a subpackage in package "posix".
posix::posix_file::mkdir # Reference a function in a subpackage of package "posix".
As shown, nonalphabetic identifiers are enclosed in parentheses when referenced as part of such a compound identifier. This is purely to solve the syntactic problem that (for example) ::| is a perfectly legal non-alphabetic identifier, so it would otherwise be unclear whether posix::| was a compound identifier or just two identifiers in sequence, one alphabetic, one not.