character-literal:
' character '
character:
single-character
simple-escape-character
hex-escape-sequence
unicode-escape-sequence
single-character: any char
except
' (U+0027), \ (U+005C), and new-line
simple-escape-character: one
of
\' \" \\ \0 \a \b \f \n \r \t \v
hex-escape-sequence:
\x xdigit xdigiitopt xdigitopt xdigitopt
xdigit: one of
0 1 2 3 4 5 6 7 8 9
a b c d e f A B C D E F
unicode-escape-sequence:
\u xdigit xdigit xdigit xdigit
\U xdigit xdigit xdigit xdigit xdigit xdigit
xdigit xdigit