casecmp?

Returns true if sym and other_symbol are equal after Unicode case folding, false if they are not equal.

:aBcDeF.casecmp?(:abcde)     #=> false
:aBcDeF.casecmp?(:abcdef)    #=> true
:aBcDeF.casecmp?(:abcdefg)   #=> false
:abcdef.casecmp?(:ABCDEF)    #=> true
:"\u{e4 f6 fc}".casecmp?(:"\u{c4 d6 dc}")   #=> true

nil is returned if the two symbols have incompatible encodings, or if other_symbol is not a symbol.

:foo.casecmp?(2)   #=> nil
"\u{e4 f6 fc}".encode("ISO-8859-1").to_sym.casecmp?(:"\u{c4 d6 dc}")   #=> nil