escape sequence character
\tex{\sf\bs\sq} single quote
\tex{\sf\bs\dq} double quote
\\ backslash
\t horizontal tab
\v vertical tab
\n newline character
\r carriage \tex{return}
\f form feed (or new page)
\b backspace
\\ tex{\em ddd} octal value (specified by exactly three octal digits)
If the octal value specified in the "ddd" form does not correspond
to a legal ASCII value, there will be a compile-time error.
Examples of character literals are
'', '7', 'a', '"', '\"', '\'', '\n', '\000'
Methods for type "char"
to_int ( ) returns (int)
% effects returns the integer ASCII code for self.
to_string ( ) returns (string)
% effects returns a one character string containing self.
lt (c: char) returns (bool)
le (c: char) returns (bool)
ge (c: char) returns (bool)
gt (c: char) returns (bool)
% effects these orderings are consistent with the ASCII numbering of chars.
equal (c: char) returns (bool)
% effects returns true if and only if self is same as c
similar (c: char) returns (bool)
% effects returns true if and only if self is same as c
copy ( ) returns (char)
% effects returns self
unparse ( ) returns (string)
% effects If self is a printable character, then returns a one character string
% containing self. Else returns a string containing an escape sequence
% that represents self.