19.2 Pathnames 19.2.2 Interpreting Pathname Component Values 188.8.131.52 Strings in Component Values 184.108.40.206.2 Case in Pathname Components
220.127.116.11.2.2 Common Case in Pathname Components
For the functions in Figure 18.104.22.168.2 Case in Pathname Components,
a value of :common for the :case argument
that these functions should receive
and yield strings in component values according to the following conventions:
Note that these conventions have been chosen in such a way that translation
from :local to :common and back to :local is information-preserving.
All uppercase means to use a file system's customary case.
All lowercase means to use the opposite of the customary case.
Mixed case represents itself.