Return t if OBJECT is a case table.
See `set-case-table' for more information on these data structures.

Return the case table of the current buffer.

Select a new case table for the current buffer.
A case table is a char-table which maps characters
to their lower-case equivalents.  It also has three "extra" slots
which may be additional char-tables or nil.
These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
UPCASE maps each non-upper-case character to its upper-case equivalent.
 (The value in UPCASE for an upper-case character is never used.)
 If lower and upper case characters are in 1-1 correspondence,
 you may use nil and the upcase table will be deduced from DOWNCASE.
CANONICALIZE maps each character to a canonical equivalent;
 any two characters that are related by case-conversion have the same
 canonical equivalent character; it may be nil, in which case it is
 deduced from DOWNCASE and UPCASE.
EQUIVALENCES is a map that cyclically permutes each equivalence class
 (of characters with the same canonical equivalent); it may be nil,
 in which case it is deduced from CANONICALIZE.

Select a new standard case table for new buffers.
See `set-case-table' for more info on case tables.

Return the standard case table.
This is the one used for new buffers.